I've run a pure troll list in SBG a few times now (see image below for army)
Although I've run them with both chains and spears, you may as well not bother. The 5+ to hit is crippling - in the 2-3 games I've played in an all troll list, I've hit once or twice with the troll chain, and
maybe once with stones. If you have to, only get two chains at most, and have them right at the very front of the army.
I work with;
Buhrdur
Cave trolls x 5
This gives a nicely sized army. Buhrdur is great in combat, lending his might where needed. The other trolls are also worth their points, especially with the new monster rules. Barge is effectively a good way to 'rescue' a fellow model in another combat, rend is excellent at decimating enemy heroes, and hurl is just plain fun, and super effective at lower defence troops.
A great combo is to start off with a hurl, and with a troll nearby, call barge. The troll can then leap onto the models who have been knocked prone, landing double strikes. I believe I pulled that off against Harfoot the other week?
Attachment:
IMG_20131231_185906.jpg