Although it's not a Cummins, this truck would make a good donor. I used to own several of these, and they are just as reliable as our trucks. All mine had Allison autos in them too. The rear axle would be bulletproof in a pickup truck
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2400878269&category=6729

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2400878269&category=6729