A photo of my home built fibreglass folding trailer caravan. I copied the Portafold/Ansfold idea of folding. Size is 6ft x4ft base, with erected height (interior) of 6ft6inches. I built it to use with my Quantum kit car. It has a sitting area for during the day, converting to a double bed for night. Again all the boards used are GRP, with foam insulation.
The caravan folds to 3ft 9inch high, to tow in comfort, and be just visible in the rear view mirror. See the 2nd photo for the view of it folded down.