After reading through the latest Editorial Comments in the Glass's guide, one of the ideas that popped out to me was the idea of having a caravan that can be configured to whatever style layout you wanted. This 'Free Format' is basically a box on wheels, with all the required safety and amenities plumed in, but leaves the main layout to the owner. Movable wall panels, dividers, bases for bunks and draws, all placed on runners sunk in the floor or outer walls, with easy fit piping for the blown air heating system. That would let you have your 4 berth setup with bunk beds and a clear floor space for the kids, but then could be quickly changed to a fixed 'ish' bed and seating area for just the two of you.
This may already be an old fashioned concept, with CarLight already doing configurable beds many years ago, but its something that need updating for the modern age for sure. What would you think about a 'Design your own on the fly' caravan?