What do you plan on doing with the truck? There are a few companies that are making 10 lug adaptors that allow for converting the 8 bolt 3/4 and 1 ton axles to the 10 lug truck wheels, so you could run a GM 14 bolt, Dana 60, 70, or 80 and have a great selection of gearing to choose from. Here is a link to the American Force site they have adapters,they are listed in sets but you could probably order the rear only. There are some other brands out there but I can't rember their sites.

http://www.americanforcewheels.com/index.php?route=adapters/index
Hope that this helps!