My 4 alt shaman have nothing more than beginner equip at Lv. 38 now. So far they don't do anything at all, and whenever I start doing runecloth stuff with tailor I'll build them up some equip and buy some random staff until they are high enough for BC and then start questing for new initial items.

And about deadmines, how many alts are you powerleveling? I found out that if you have 1 70 and 1 lower level alt compared to 1 70 and 4 alts, you get alot alot less exp per kill with the group of 2 than 5.

I think the way it works is that since the medium of the group of 5 is lower than the group of 2 is lower they get more exp per kill. I was 1x70 and 4x10-18 in Deadmines and I would get about 50-70% of a level a run. I didn't spend more than a single afternoon in Deadmine.

*edit* Personally, I don't care much about rep from SW, IF, Darn or Exodar (for either if I were horde). At 70 I don't spend time there, even less buy anything and rep for those faction are useless. Although if you meant for TBC, then I totally agree, the items from quest are really worth it until you get to run Lv.70 instance.