[hotrodder]

It is the same in theory as making a long bed shorter. Figure out how much you want to add to the length, get another long bed and add to the bedsides .I would think you would have to add to both ends to make the wheels centered in the wheel openings. Lengthen the frame and get a new driveshaft, done deal. I'm sure someone around you could do it. I have done three shortening beds, never had anyone ask about going the other way. Pull trucks do what you are asking about