He neglects the camper overhang on the rear . Some people will slide 4 ft extension in the receiver to pull a boat ? Kevin .
...in some photos there even is a motorcycle on the back of it....
When i was still in truck body building 14 years ago, manufacturers had exact body builders guidelines, especially for lighter trucks, with exact specifications of the position of center of gravity of the superstructure.
We once had a situation with a Sprinter long wheelbase for a dealer of ours, who sold a tool cabinet behind the cab. When we heard that the dealer promised it to hold 1000kg of power tools (without consulting with us first), we delivered it with the tool box on the 5th wheel trailer and let our dealer decide if he wanted to place it behind the cab at his own liability, because it would grossly overload the front axle as well as the frame.
Off course the supplier of the slide-in camper doesnt assemble the truck and camper so they bear no responsibility for the combination, and light commercial vehicle dealers hardly know extensive body builders guidelines even exist.
If i were the mans lawyer i would check if Ram bodybuilders guidelines apply to the chassis-cab only, or generic. If theres no guideline from Ram that tells this isnt possible, you might have a case. If not, youre on your own with the 17.000 dollar bill and an unsuitable camper for your vehicle....
Another issue with a slide in camper is the high center of gravity: When you hit the gas, truck accelerates under the camper, causing an extra rearward tilting force on the frame. At the same time, the truck grips on the asphalt trying to turn the wheels forward, thereby putting a reaction force on the frame, further increasing the bend back over. A pickup is not a truck, its a light commercial vehicle, built to a weight, and designed to take payload with its CoG only slightly in front of the rear axle so the front axle doesnt carry much other than occupants and drivetrain.