How much truck for a shortbed TC with a slide?

The Lance 855s is made for a short bed truck. Although it has been done, placed on a long bed truck there would likely be a space of a foot or more between the camper and the front of the truck bed. Not sure the center of gravity would be as good on a long bed as on a short bed? Ford and Chevy/GMC don't offer DRW short bed trucks, only Dodge with the mega cab.