Just about the best setup you can get is 23 splined duals with 4.7's in the rear case and a rotated adapter.
As for the crossmember be ready to beef up the FROR one, they have a habbit of breaking in the bottom right corner. Check out 4x4innovations crossmembers also.
If you have a full transfer case and 2 crawl boxes, you might want to consider picking up a regular MC07 adapter and run tripple cases. It's a nice setup.
