Aero trailer:
With the boattail installed, it's no higher than the minivan pulling it. It's a box, but it's a smaller box than the TV.
Campers are one of those places where you can't have your cake and eat it, too- usable interior space and effective aero work against each other. The practical limitations (amateur drivers and people who strap gear all over the place) are worse for campers than big rigs. I just don't see any improvement for production models.