Well, the Ramchargers have a 106" wheelbase, and the first-gen and second gen Dakota has a 112" wheelbase in regular cab short bed models. It would probably be easiest to use the Ramcharger for a base, depending on the amount you can fudge the wheelbases or slightly relocate the leaf spring perches. You might be able to bring a Dakota's rear axle forward, but I'd think the Ramcharger would be easiest. The Grand Cherokee also has a 106" wheelbase.