A utility body was not in my budget, so I looked at aluminum and steel beds. Without customization, none of the stock aluminum beds suggested using it to tie down the camper - This raised the cost too much for me and it approached base pricing of a utility bed.
I chose a stock steel deck with boxes hung under it forward of the axle. Once I have the Mammoth, I will decide whether to enclose the wings or just add additional boxes to fill the voids above the deck.
Regardless of bed choice, decide how and if you will tow behind it. None of the integrated receivers with the decks had the capacity to tow my heavy trailer on an extension, so I would have needed to customize or select a deck that would allow the SuperHitch to fit under it.
Host Mammoth 11.5 on Ram 5500 HD