A 12 team league with divisions could have a nice 16 game schedule. Home and home with the 5 other teams in your division, alternate home and away yearly with the other division. That way you build rivalries within division and still play everyone every year.
East: Villanova, Georgetown, Providence, St John's, Seton Hall
West: Marquette, DePaul, Creighton, Butler, Xavier, Dayton
Personally, I would like to keep Dayton and Xavier together if we added them. I'd also like to keep the original five East Coast teams together. I know geography can't be the only factor, but it sure makes VCU look attractive. I'm sure those East Coast teams would rather someone closer to home too.