Depends on whose kidney, and how good your metalworking skills are
AFAIK, all alternatives require relocating the rear calipers. Now that I've said that, someone may pop in here with one that works.
You can swap to the 89 calipers, brackets, and rotors - they're a bit beefier.
THAT said - someone noted that Gen1 Dodge Vipers use the same shape/size brake pad, so it should be possible to upgrade the pads some.
OTGH - do you lock up your wheels now? When you hit ABS, are all four wheels thrumming, or just the front? If the back is already locking/ABS'ing on you, more brake won't do any good until you fix the tires. And since the front brakes do most of the braking ANYWAY ...