there was such an option- I forgot who makes it- It had legs that extended down that could support itself. In the ad, they designed it to be "quick releasE" so that a single person could setup and remove it- just pull the pins, use the included lift jacks on all 4 corners, and then drive forward. It was designed almost more for consistant uptime, such as for a fleet that has specialized tools and equipment, and the truck needed servicing. Cool idea, too bad it was mega bucks.
Im sure you can probably design any camper to have similiar features, but it would require the flooring and outside structure to be strong enough to be self supporting.
I would love one too, except also for that "difficulty of removal" thing.