Lots of new cars have really nice supportive seats, so if you go look around the car dealerships you can get some ideas. Otherwise, there are lots of aftermarket choices as well. I would doubt any current Chrysler seats would just drop in without having to fabricate some brackets (the inboard seat bracket is about 1.5" high, while the outboard seat bracket is flat due to the E-body floorboards.
I'm putting Recaro seats from a late 70's BMW in mine. I fabricated some mounts and used a universal type slider. Here's some mock up pictures (I was trying to make sure I'm happy with the seating position and height, etc.). I'm real happy with the seats... they are very supportive without looking too out of place in the car.
Travis
72 Cuda