My thoughts exactly. Since you are above the profile of the cab why not do a cab over bed? I bet they have a good reason but to my ignorant eyes it would seem to add a lot of space and not that much weight. Wonder what the cost would be? For 130,000 a cab over would make it much more dare I say practicle?
re: cab over versus no cab over configuration
i do not know if it is one of the reasons for the no cab over design, but surely it could be one of the benefits:
to access much of the engine for repair, including ordinary parts like a water pump, one has to either: remove the cab (a 20 min. procedure by an experienced technician), or remove the engine through the radiator opening. The latter requires special hoists and is a very long procedure.
Thus the lack of a bed space over the cab may preserve the option to remove the cab to perform needed repairs. Cab over beds, as on the EarthRoamer, prohibit this, and force one to remove the engine to repair inaccessible parts.