I have an old '68 Jeepster Commando that I bought as a project for my son and I to work on together. He lost interest, I don't have time for it now, so it's sitting completely (and I do mean COMPLETELY) disassembled in my garage. It originally had a AMC Dauntless 225 cid V-6 engine in it, but that engine needs to be completely rebuilt. I was thinking along the lines you mention, buying a "bad" Carpenter and taking the diesel engine and tranny out and installing them in the Commando. It would probably be a cheaper way of getting a working engine than having the old one rebuilt. Since I have the entire vehicle disassembled, and since I need to replace much of the floorpan, I could probably go ahead and cut the firewall and floor to fit the new powertrain, and lengthen the frame and move the engine mounts as necessary.
I guess I'd need a detailed plan of the replacement engine candidate first in order to see if there was a reasonable chance that it and the tranny could be mated to the vehicle.
Or I could just wing it....