I've got 8 in a 10 gallon right now - but 4 are Deborah's that I'll take to her tomorrow. Even with 8 - it seems plenty roomy for them.
Here's a good website on ASF's http://asfrats.info/
And here are some pictures of Deb's and mine:
I've also seen some nice lighter colored ones - I'd like to find some of the other colors as well.
They really don't need a lot - fresh water (get that metal cover for the bottle though so they don't chew it) a small hide like in the picture, a small exercise wheel, Mazuri lab block. I just picked up some millett and timothy hay - they went Coo Coo for Cocoa Puffs over the millett!