What's the tonnage rating on a 6500, about 2 1/2 tons or so? I believe the running gear from a single-screw road tractor, engine, transmission, axles, air brakes, etc., should fit pretty well. Find an older Mack, Freightliner, Peterbilt, or such, buy the whole rig, and transplant the power train. That project should keep you out of the local beer joint for several months!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!