Yes VB Airsuspension. We have VB-FullAir 4C including the self-levelling option. So long as the suspension variation across the 4 corners will cope with the slope it will provide a level van. It is not as fancy as some air systems but is as close to VW approved as you will get.
Full Air Suspension: VB-FullAir 4C: Volkswagen » VB-Airsuspension
There doesn't need to be a button for each corner because the suspension system levels automatically without the need for user input.
Interested but depends on cost, how much did you VB set you back