[SRD art]

S10's came with a 7.5" rear and don't hold up well to a great deal of power in stock form. 10 bolts are pretty strong. An 8.8 from a Mustang would be ideal, that's a tough rear and newer ones come with disc brakes. Trouble is 5 on 4.5 bolt pattern but you can have that redrilled.

Are you just looking for fat meats or a deep offset? Seems fat meats can tuck with a stock frame and the right offset wheel. Maybe widening the tubs just a bit too?

Wheel Vintiques makes steel rallies up to 14" wide and will do custom offsets. I ordered 6 lug Corvette style rallies for my 76 Burby in 15x8. They were cheaper through Summit Racing than direct through Wheel Vintiques. That was several years ago, but I imagine that's still the case.