Could still be the transfer case if it's 4wd, won't know till you get it out and check it ...
I've never heard of a fiberglasss driveshaft, I'm pretty sure that thing would have shattered in the situation you just had. I'e heard of Carbon Fiber shafts and I bet it would have done the same thing.
As for the tranny rebuild I did mine at home by myself. I used a rebuild kit with Alto red clutches and band, Kolene steels, "the beast" sun shell, all new Torrington bearings, Superior Shift kit with all the mods, new Transgo separator plate and a new torque convertor. Basically all the std stuff in a "stage 2" rebuild. It's going on 100K miles and shifts perfectly. The only thing I didn't do was adjust the lil shift motors. Figured it was a truck, neck snapping shifts in a big SUV = broken parts somewhere. Looking back I guess that didn't matter seeing as how I ripped a tranny mount in half and busted my rear end anyways. LOL
Ohh yeah get yourself a new tranny mount a the biggest cooler you can find for after the rebuild.