In shattered halls there is a way to keep spawning non-elite mobs. Basically:
When you get to the part that throws fire at you, just train to the very end, but don't attack the last 2 groups of mobs. Stop at the last corner with lava on the right. Get your part into this corner and kill off your train.
There should be one group of non-elites left and one group of elites. You can now sit in this corner safe from the "Fire" that gets thrown out, and 2 non-elites will spawn every 15-20seconds. They are only worth 2rep each, but we spawned them for over half an hour.
This works great if you've got alts on other accounts, you can run up here and all but 2 of yoru group go afk. Me and the guild took turns going afk and netting rep.
It is no where as fast as doing a regular run, however, it is much easier and can be done afk pretty easy.