Yea,
I hear you on the dually problem. If only Ford made a longbed truck with a extended wheelbase, and put on the 19.5" rims in single rear wheel configuration, with a 4,000 pound rating per tire, it would be sufficient enough to have a 13,500 pound GVWR, and by extending the wheelbase about 9" it would put the weight farther forward, loading up the front axle, so the truck can carry a lot more weight, without nearly as much on the rear axle.
In a camper situation, the 9" longer wheelbase would put the center of gravity well ahead of the rear axle, and transfer a lot of the camper weight to the front axle.
In a fifth wheel situation, it might be possible to have the rear wheel opening just in front of the bumper, giving more clearance for the tailgate, and placing the hitch center about 2" in front of the center of the axle, transferring more weight to the front axle, and also making it possible to turn sharper without the front of the trailer reaching the cab window - remember the 9" longer wheelbase would mean the trailer pin would be overall 8" farther from the cab. A 7' bed might be enough to tow a fifth wheel without a sliding hitch.
Or with a 8' bed, if the rear axle is far enough back, then there might be space to mount the spare tire in the compartment in front of the rear axle, on the passenger side, like the old 72-75 F-350 Super Camper Specials had. The Cuper Camper Special had a 140" wheelbase instead of the 133" wheelbase, bringing the axle back 7" and they did install a compartment to carry the tire in the bed, behind the passenger door. It was a 30" square door cover, the tire acess was to the outside of the bed, and you could get it on and off while a camper was on the truck.
Probably one of the best features that Ford offered to camper buyers back in the 70's and 80's.
Fred.
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