Check out this 66 GMC/Cummins pickup. Met him at the dunes this summer so I got to see it in person. He loved his 66 but wanted it to perform like a new truck so he bought a new dodge and cut it down to the firewall-floorboards-back wall up to the rear window and grafted the 66 sheetmetal to it. The thing is cool as hell! I liked his comment, "When it was all done I climbed in, hit the key and drove off with a new truck. No issues with mating wiring, trying to make this component work with that component, ect." He said he only had to extend a few light wires a few inches was the only wiring he had to work on. Maybe another way to go on your project?
http://www.trucktrend.com/cool-truck...-camper-truck/