Based on a converted hightop panel van, the D'ieteren 'Weekender' has some really novel design ideas inside.

Firstly you notice that the rear end is a kitchen/ storage area. It features proper rings over the engine area with a window tunnel to the rear hatch.

To the right of this is a tall wardrobe/toilet cabinet. Quite narrow so I assume it's purely for storage.

In the front there is a middle 2 sweater bench and a pair of cab seats. These all fold flat and merge to become a 3/4 bed.

Lastly over the engine bay is open storage when accessed from the tailgate. It's shown in the pictures with a lady shopper but the plan shows it designed to store a mini moped/Motocompo monkey bike.
Although this conversion was innovative I think it has its problems (bed comfort/size for starters) but it certainly opens the eye to other possibilities.