below are pictures of the bed setup in my van. It is designed to hold 2 pax of medium posture ;) and allows to keep a lot of space in the back. It is fully reversible and does not require any special mods to the interior other than removing 3rd row seat.
1. "soft" luggage is placed between the middle and front seats . From under the middle bench I pull out a "custom- made" piece of wood board to fit on the seat and centre isle ( how do you call this thing behind front seats anyway ? )

2. This is how it looks :

3. Lay flat middle seat. Jump seat remains folded. I put a flat box under the seat for extra support. Remove headrests ( they can stay, but then they raise up one end of the mattrace )

4. Inflate a nice comfy airbed ( double twin size, 100 cm wide ) and put on top :

5. slide the curtains and go to sleep :)

you can see a doble voltage fridge ( 220/12 ) and an air heater ( 220 ) - it was pretty cold at the sea side this spring !
There is pleanty of room around the bed to walk, change clothes, eat etc. if the weather is bad.
When the seat is up and frigde moved to the side 2 bikes can be accomodated inside :

The setup worked nice and my wife accepted it , phew ;)

Comments welcome !