As someone previously mentioned, the bed in the sleepers can be removed, leaving a large empty space all the way to the floor. Then install a fold-down bed/seat, or even just seats. For that matter, those sleepers have doors on at least one side, sometimes two. You could put ONE seat in the sleeper, away from the door; and be able to access dry storage space from inside AND outside the truck through the side door. In fact, they usually have 2 doors, a small lower one and a large upper one. Build a "dirty" storage on the bottom for tools, chains, whatever...and "clean" storage above for stuff for trips- camping gear, groceries, whatever.
Matching styles- I think you might be surprised just how well one of the small sleepers will match the lines of a Deuce. Look at the back of the Deuce cab- its curved. Look at the rear of the roof (hard OR soft top): its curved. Put the sleeper on, paint to match, and I think it will look right at home.
Jim