After some time and deliberation, I have (finally) managed to develop a modified version of the SBG rules, which uses a 12-sided dice rather than a 6-sided one.

The problem is, I am far from my models, and so cannot play test it myself. It should be fairly balanced, though changing the dice does change the game mechanics a lot, and so the effect could be quite dramatic.

The large drawback that I always faced was that under a D12 system, fighting skill becomes almost irrelevant. However, I recently had a breakthrough on that front, by adding a rule where warriors may re-roll dice to win combats when their result is smaller than their fighting skill.

Anyway, history aside, the rule set is more-or-less complete. D12 allows gamers to play more detailed games than with a 6 sided dice, without adding too much additional complexity, and tedious dice rolls.

While the rules I have developed can be used with the existing unit profiles, I would ultimately like to re-work the SBG profiles to allow more differentiation between ordinary warriors.

The rule list is long, so I won't post it here, but if anyone is interested I can email it to you.

couldn't you just add fight skill to the total?

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I think a drug habbit would be cheaper...

I thought about that, but it causes a problem when you have a large gap between fighting skill. For instance, how would one defeat the Balrog if you choose an army with only 3 fighting skill warriors?

In any case, the arithmetic would overwhelm any sense of enjoyment in the game, so a simple mechanism is better.

true but it does bug me that a big diference in fight skill dosn't translate to that much on the table.

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I think a drug habbit would be cheaper...

you could total the fight values so 2 f3 warriors are equal to 1 f6 warrior. But i guess the additional maths takes away the simplicity.

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I think a drug habbit would be cheaper...

That is a great solution! Simple, and pretty potent mathematically. Everybody has a chance at a reroll, and elves will get a lot of them. It also solves the "degree of difference problem", which means elves will be better against goblins than against uruk-hai.

However, this will completely unbalance the point system...you will need a LOT more goblins to take down elves. Currently elves 1:1 have a 16% advantage (ignoring Courage effects). I'm not sure how to work out the probabilities with this change, but now goblins will get a 16% chance at a reroll, while elves will have a 42% chance at a reroll...seems like elves will win over twice the number of fights as goblins because of it.

Is the system D12 for wounding as well?

GilGalad is awesome in this system...
D12 I roll a 12 I win.
I roll less than a 9 I reroll.

So the only ways I lose is 9,10,11 and I can might dice?
I think might could be over costed in the D12 system too 5pts to change a 6 into a 7 is not great if you opponent has a 12

can you re-roll a re-roll? or do you have to stick with your second roll no matter what, even if it is less than your first roll?

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I think a drug habbit would be cheaper...

SBG already has a "can't reroll a reroll" rule, this shouldn't be different.

Good catch. That would make the whole gil-galad thing a lot better. He's awesome, but not almighty.

Agree, this shouldn't be different, but I wanted to clarify if the intent was the same.

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I think a drug habbit would be cheaper...

Sorry, I've been tied up, so am a little slow to reply.

I'll just try posting the rules in full and see how it goes.

D12 Rule Set for SBG

Introduction
Like many fans of the game, I’ve always enjoyed delving into my own personalised house rules, tweaking the odd hero, inventing a new unit here and there. All was well at first, but it wasn’t long before the existing set of rules began to leave a little to be desired.
The biggest problem I found is that the unit profiles tended to be crowded around 3 or 4 Fighting skill/strength, with no ability to squeeze anything in between a regular troop, and an elite. Clearly (at least from my perspective), this leads a lot to be desired, and it was this which motivated me to develop this new rule set.

So, what is D12?
D12 is a house rule set for SBG which uses a 12-sided die rather than a 6-sided die to form the basis of the game. This brings a number of advantages to the game, as 12-sided dice have twice as many possible outcomes, and therefore provide much more scope for new house rules and unit/hero/weapon abilities.
D12 is strongly founded on the original rule set for SBG developed by Games Workshop, and has been designed to follow the aesthetics and play style of SBG as closely as possible. In many cases, the game simply requires a 6-sided dice to be replaced with a 12-sided one, though there are a few fundamental changes to the game’s mechanics. For all rules which are not explicitly covered here, you may either follow the existing rule set (using a 6-sided dice if necessary), or you may develop your own.

Won’t changing the dice completely change the game?
In many ways, D12 is very similar to the D6 version of the game. There are a few places where fundamental revisions were required to adapt the game. These revisions, in my opinion, go some way to correcting the deficiencies of the original game, and should not require a steep learning curve (and don’t forget, if the game were exactly the same, why change the dice?). The two greatest changes are the new D12 wound chart (which, at least in terms of probabilities, is similar to the D6 one), and a change to the role of fighting skill (this was necessary as the chances of getting a tie with D12 is half that for D6, greatly diminishing the value of fighting skill).

So, without any further ado, the rules:

D12 rules
The basic idea of D12 is, wherever you used to use a D6 roll, you will use a D12 one. For your ease of reference, the following rules changes will be discussed:
• Priority
• Jumping and climbing
• Shooting
• In the way
• The D12 wound chart
• Combat
• Courage
• Spells
• Might
• Fate
• Optional: Weapons
There is no doubt something important that I have forgotten. If this is the case, feel free to develop your own rules, or use the existing rules with a D6. Also, I haven’t read the new Hobbit rules, or Warbands, so any changes which have been introduced in those new revisions by Games Workshop will not be covered here.
I have made efforts to keep my descriptions of the rules as brief as possible, so that this document can be used as a convenient reference. For a more detailed description of the rules, please refer to the official rules book, and bridge the gap with a little imagination.

Priority
Simply roll a D12 instead of a D6. In the event of a tie, the other player moves first.

Jumping and climbing
When jumping or climbing over an obstacle, roll on the table below:
Result Consequence
1-2 Warrior fails to make the jump.
3-6 Warrior scurries over the obstacle, but can more no further that turn.
7-10 Warrior leaps over the obstacle, losing 2” to his movement.
11-12 Warrior leaps over the obstacle effortlessly, and may continue to move as normal

If a rider is thrown, roll on the thrown rider table:
Result Consequence
1-2 Warrior falls beneath the horse, suffering a S6 blow.
3-4 Warrior falls head first, suffering a S3 blow.
5-7 Warrior falls uncomfortably, and will be placed lying on the ground.
8-10 Warrior makes a quick recovery, may stand, and if charged may fight back, but may not strike to wound.
11-12 Warrior leaps from the horse and straight into action, may complete his move, and act as normal.

Certain circumstances may modify the mobility of different warriors. Before performing a jump or thrown rider test, consult the chart below to see their bonuses/penalties:
Circumstance Modifier
Heavy armour -1
Armoured horse -1
No armour +1
Expert rider +1
Tall obstacle -1
Slippery surface -1
Smooth surface -1

Other ideas for modifiers are welcome.

Shooting
Clearly, hitting on a 4+ when the dice you are rolling can go up to 12 is pretty effective.
When determining what result an archer needs to achieve on their to-hit roll, please consult the table below.
D6 to-hit D12 to-hit
2+ 3+
3+ 5+
4+ 7+
5+ 9+
6 11+

One thing you’ve probably noticed is that using D12 there are more options options for an archer’s shooting skill. While I won’t offer example profiles here (this article will be long enough as it is), I would encourage you to consider taking advantage of this and developing your own house rules for your archers.

In the way
When shooting, and an opponent is partially covered, roll an in-the-way roll, except note that the shot will hit on a 7+ instead of a 4+. If you would like to make some shots easier than others, the following table contains a list of suggested modifiers:
Circumstance Modifier
Target is behind heavy cover -1
Target is shooting form a fortification -2
Target is behind light cover +1

The D12 wound chart
The following is the full D12 wound chart.
S\D 1 2 3 4 5 6 7 8 9 10 11 12
1 7 8 9 10 11 12 12/4 12/7 12/10 - - -
2 6 7 8 9 10 11 12 12/4 12/7 12/10 - -
3 5 6 7 8 9 10 11 12 12/4 12/7 12/10 -
4 4 5 6 7 8 9 10 11 12 12/4 12/7 12/10
5 4 4 5 6 7 8 9 10 11 12 12/4 12/7
6 4 4 4 5 6 7 8 9 10 11 12 12/4
7 4 4 4 4 5 6 7 8 9 10 11 12
8 4 4 4 4 4 5 6 7 8 9 10 11
9 4 4 4 4 4 4 5 6 7 8 9 10
10 4 4 4 4 4 4 4 5 6 7 8 9
11 4 4 4 4 4 4 4 4 5 6 7 8
12 4 4 4 4 4 4 4 4 4 5 6 7

There are a number of important changes I would like to point out (aside from the obvious change in numbers). First of all, unlike the original chart, where (for example) there is no difference between a defence 4 or 5 warrior when being struck by a strength 3 enemy (each would be wounded on a 5), every value of defence as a unique to-wound requirement for any given value of strength. I believe this is an improvement, as it diminishes (among other things) the very dramatic difference observed between 5 and 6 defence warriors when facing strength 3 opponents, and so should help level the playing field somewhat, and shift the focus of the game (slightly) from army selection and towards tactics.
The other difference you may notice is that many warriors will now be much easier to wound. I had the choice between a game where warriors are stronger, and one where they are weaker. I chose weaker as this will speed games up a bit, and level the playing field further for many troops. If you feel this makes archers too effective (which is a concern of mine), you can either reduce the strength or accuracy of archers, or increase the defence of each warrior. If you use a lot of cover in your battlefields, it may not be required.

Combat
In combat, warriors will (obviously) use D12 instead of D6 when rolling to win and wound.
Using a D12 does have a big effect on fighting skill, however, as warriors are now only half as likely to tie.
In addition to automatically winning tied fights, fighting skill will now allow any warrior to re-roll his result whenever he scores a result to win less than his fighting skill (if he chooses). A re-roll may not be re-rolled. Also, if both players have the option to re-roll, they must do so at the same time.
So, for instance, imagine four 3 fighting orcs against a 7 fighting skill elf lord. The orcs score two 2’s, a 4, and a 12. They may re-roll both of their 2’s, as these are equal or less than their fighting skill (3). The elf lord scores a 1, a 7, and a 9. The 1 and 7 may be re-rolled. If the elf lord then scores a 12, he wins as he has greater fighting skill than his opponent.
This also somewhat resolves the problem of heroes who have dramatically higher fighting skill values receiving no additional benefit compared with a warrior who has only one more point of fighting skill.

Courage
Instead of rolling 2D6, you will roll 1D12. This will change the probabilities a little, but will make the difference between higher courage values (say, 6 and 7) more dramatic.
Spells
Just as the accuracy scores for archers needed to be changed, so too must the spell casting rolls:
D6 to cast D12 to cast
2+ 3+
3+ 5+
4+ 7+
5+ 9+
6 11+

As with archers, you may now modify the effectiveness of spells with house rules to better reflect how you feel they should be.

Might
When using might to alter to-win or wound rolls, it is much less powerful when the dice has 12 possible results. To compensate, heroes may receive +2 on their result for each point of might spent.

Fate
Fate will be passed on a 7+, and not a 4+.

Optional: Weapons
One of the great advantages of D12 is that it allows much more subtle changes to “to-win” rolls than is possible with D6. Imagine, for instance, if a warrior received +1 to win when there are only 6 possible results. After all, you would be looking at a one-in-three change of getting a 6 or 5 (and therefore counts as a 6)! On the other hand, +1 to a D12 system is much more subtle.
I have compiled a list of proposed weapon rules, which help differentiate between different weapon types.
Weapon Cost Effect
Sword 2pt +1 to win
Axe 1pt No effect
Mace 1pt -1 to win, but results of a 7+ to wound may be re-rolled
2-hand sword 1pt -1 to win, but +1 to wound
2-hand axe 1pt -2 to win, but +2 to wound
2-hand hammer/mace 1pt -3 to win, +1 to wound, and results of a 5+ to wound may be re-rolled
Spear (not throwing spear) 1pt Allows supporting. Furthermore, cavalry will not receive fighting skill re-rolls to win.
Pike 1pt Allows supporting. Furthermore, cavalry charging the pikeman or the model he is supporting will not receive fighting skill re-rolls to win.
Orc bow 1pt Allows shooting. -1 to win in combat.
War Pick 1pt -2 to win, but can foul shields if the warrior scores a 12 to win (before penalty). This effectively removes the opponent’s shield.
Dagger Free -2 to win
Shield 1pt +1D, and allows warrior to defend by shielding
Lance 1pt +2 to wound when charging, -2 to win when charged
Horse Varies Charging bonuses. Furthermore, foot troops who are not armed with spears or supported by pikes cannot re-roll for their fighting skill (this applies regardless of whether the horse charged or not).
Banner 25pts Extends the range of any standfast or heroic action the banner is in range of by 6” around the banner.

To incorporate these rules, assume that the base profile of each warrior includes one basic 1pt weapon (which you can choose). Additional weapons are as priced. Alternatively, you may swap the basic 1pt weapon for a more expensive weapon (such as a sword) for the price difference. So, a sword armed model would cost 1 additional point.
Note that an orc may select an orc bow as his hand weapon.
Weapons which are not mentioned are unchanged from the existing rules.

Well, the wound table doesn't display well, but it has been adjusted, and I expect it alone could change the balancing. In fact, most of my tables are a mess.

Whafrog. It will benefit elves more, but since you are less likely to tie with fighting skill, the advantage is offset somewhat. Also, the changes I have made to the wound chart make everyone a little bit easier to wound, so that will work to the advantage of lesser units. Ideally, I would like to rework different profiles so that the Balrog has 12 fighting skill, elves would have 7, then you'd be able to squeeze a few new levels in between warriors and elites such as the fountain guard. That would bring up the price of elves, of course, but that would help with the game I think.

Also, you can't re-roll a re-roll.
It would probably be worth changing banner rules as well (or you'll have too many different re-roll rules), but I haven't thought of anything better yet.

Edit: I will try my hand at calculating the probabilities of winning for a few different combinations of troops and upload the results in the next few days.