What about a roll-off dump trailer, with a dump box and a flatbed ?
You see it a lot in Holland, they load the flatbed while rolled off, drive the equipment on the deck, strap it down and then winch the flatbed on the truck or trailer. The next day they pull a dump box on the truck or trailer and use it as a dump trailer, while the flatrack with equipment stays on the jobsite.
I have been sketching and calculating some on a 5th wheel with a tool cabinet on the gooseneck and a roll-off dump bed in the back, using a Warn 12V winch to pull the dumpster or flatbed on, and a hydraulic power pack to tip the roll-off frame. I never did anything with the idea because it was at the time i changed jobs, away from the trailer business.