Bed size vs. Camper size - Flexible?

Thank you!

Isn't there one of our fellow TC'ers who put a short bed camper on their long bed truck and then installed a Honda EU3000is generator in front of the camper?

My camper is designed for long or short bed trucks. COG is right over the rear axle on my short bed.

As long as the camper is secure, there isn't a problem putting it on a flat bed.

There are several campers that are listed by their manufacturer as suitable for a long or short bed truck. These are rare.
Most long bed campers on a short bed will put a lot more weight on the rear axle and wont' be supported properly where they overhand.
A shortbed camper on a long bed truck will have a gap at the front because you can't slide it fully on or the taillights will hit. I've seen people use this gap to haul generators and other things. It looks funny but seems to work fine.
I have a flatbed with tool boxes above and below the bed for extra storage. I can put tools, lawn chairs, ext. cords, oil and other fluids, my grill, propane bottles, etc. in all the storage compartments. I don't know why a flatbed would be considered "unsafe". They make an excellent platform for hauling a TC.
I wouldn't want a lifted truck and the top of my camper is already 11.5' and I don't even have a basement. Some lift kits can be easily removed and the truck returned to stock IF you have all the factory pieces that were removed to install the lift. Some truck's need some of their factory parts or brackets cut off to install the lift. Returning them to stock would require welding these parts back together, again, IF you have them in the first place.
I'd skip the lifted trucks.