The center of gravity is placed over the rear axle by design. It is different for a long bed versus a short bed truck. The camper will hang out past the rear of the truck by 18" or more for the models with a head.
In good used short bed models there are the Lance 830 and 845 models and others like the 850 from Wolfe Creek. Lance has brochures with specs online for prior year campers so you know when you see a used one for sale what the layout is like, size of fridge and holding tanks, ballpark weight, and dimensions.
