because I have a 6800 pound van and live in the Rockies and drum brakes suck.
I've thought about this myself for our G1500. We don't have anything like the Rockies here in the SE but we do have some excellent mountain roads. We like to drive the Tail of the Dragon and the Hellbender in our GMC, but only
when it's deserted in the winter.
Oh, you asked for thoughts:
The rears really only do about 30 to 40% of the braking. You have 11' x 2.75" drums which are pretty darn good and kits are very pricey. So I guess it's a cost/benefit thing.
The disks may not fade as bad and while that's possibly the only advantage, it IS an important advantage. And they do look killer with the right wheels. The black dust is a PITA.
The mid '90's Impalas (and a few other GM cars) had disk rears. If those parts from a donor could be utilized (and maybe upgraded) that would keep down costs and make future maintenance a breeze. The Chevy pick-up forums have threads on this swap IIRC.
If going with the disks you might swap to the mid 90's G20/G30 hydro-boost power brake booster if yours is currently a vacuum assist. They have a little more grunt.
If you change the brakes you'll need the axles out, good time to replace the axles and bearings.
I'm outta thoughts but would like to see pictures and a build thread if you decide to go to disks.