The Bedford Bambi and the Romahome are both excellent little campers but they don't meet the OP brief. The space above the drivers cab is too small for an adult bed although it will do for a child. Also the nearest you get to a toilet compartment is a porta potty under one of the bench seats.

I have had a Bambi for nearly fifteen years and am about to let it go, but a deal has been agreed with a neighbor. The Bedford part of it died six years ago and the Bambi part was moved onto a Piaggio Porter pickup. This has a 1.4 diesel engine which has proved much better than the 1.0 liter petrol engine on the Bedford. I'm going to miss the raised driving position but it's time for me to change to a small car.

Something based on a Ford Transit or similar sized van will be needed to meet the brief.