Have you thought about having a pop top fitted to a Brotherwood wheelchair-converted Multipla? There's a lot of work that goes into the conversion and I reckon the dropped floor could make a decent little camper (along with said pop top). Prices for Brotherwoods used to be silly, but the roundnose Multi ones aren't too bad now. There's a nice low miler diesel one that's been on ebay for quite a while.