Sportsmobile?
I haven't any personal experiance with Sportsmobile products, but I did investigate converting my dad's van (turned out to be not heavy duty enough for the things I wanted) and I found the company to be very helpful, flexible (provide everything you want and only what you want) and more reasonably priced than the other class B companies.
Being tall, I particularly like their 'pop top' feature, which allows me to stand up in the camper while stationary, and not worry about height clearance while moving.
They will provide you a kit to design your own layout, so you can make it exactly what you need for your purpose. It's been a while, so I don't recall if they will fabricate a piece of furniture for you which is not in their standard catalog.
Note that the Sportsmobile, like all class B RVs, is TINY inside. It is great for going from point A to point B, with overnight stays, and can provide better gas mileage and get to more places than a bigger unit. However, two people trying to live in it for any length of time may get tired of the confinement quickly. And it does not have the space or CCC to carry large amounts of stuff (although you may be able to tow a small trailer).
