Aerohead, that stuff by Don Bur is phenomenal! I had never seen his work before.
capturedbyrobots, I was sitting here watching netflix and I was wondering if it wouldn't perhaps be easier to build on to the rear of the box as opposed to building up for a sleeper birth. Rather than adding frontal mass, use the idea of the tear drop shape to build an aero unit on the back to hold a bunk and your personal gear. Figures below, design 1 and 2, from the NASA link provided by jedi_sol. Design of the sleeping quarters would be dependent upon the adoption of egg or aero back... Then it would be a simple matter of accounting for the space above the cab from an aero standpoint rather than the addition of space standpoint. One could heat/cool the whole box since it's small, or simply control the back add on. The unit could hinge, allowing it to swing out of the way for loading and unloading. Or one could cut a door in the side of the box allowing the rear unit to be more permanent and allow for easier design and installation.
One need only look to small teardrop campers and overland/expedition resources for ideas on small and efficient sleeping quarters. Better yet, boat design!
~C
Design 1:
Design 2:
