From the pictured prototype, they could have chucked the absorption fridge, imported a propane fuel cell from Truma (they sell them in Europe), and have gone with a compressor fridge. Or they could have gone with an EFOY methanol fuel cell.
Custom RV doors for the generator, stove vent, and furnace would be cool as well, rather than the usual painted stuff. This is the difference between a top tier diesel pusher versus an entry level model.
I shouldn't be cynical, but if someone charges $700,000 for a rig, it better be engineered with every inch done right to be worth the chunk of change.