I've known two guys that built them. One was huge, and he used it as a camper/race car hauler. Had a stove, 'fridge, beds, etc. Took him years to build. Other one was very well done, but shorter and only carried his tools, spares, and race car. So every evening, he had to drive the beast to eat and go to the motel. Both were purchased cheap, were worn out, ate gas like a starved hog in a corn field, and took forever to build to a safe and funtional level. Each one had to have ramps that were longer than most enclosed trailers I've seen.

But they looked cool!