If you're determined to do a resto-mod, why not consider grafting the sheet metal onto a complete Dakota frame and powertrain? The Dakota has a very simple rectangular tubing frame that can have the wheelbase altered easily with a 45 degree angle cut and some fish plates at the graft. Start with a long bed Dakota, and shorten it to fit the Chevy wheel openings. All you need to do then is shorten the driveshaft. You could even opt for the V-8 Dakota if you want a little extra performance, although both Dakotas I own have plenty of power with the V-6. Then the entire 3600 rolling chassis could be sold to a restorer with more conventional requirements.
Your checkbook will need some CPR, no matter how you choose to do a resto-mod! Good luck!
Jerry