If you haven't been there already, check out the Sprinter Source forum:
That would be perhaps the best place to find an eligible van.
FWIW, it sounds like you don't want anything very elaborate, which to my mind opens up the possibility of buying most any Sprinter you like and supervising having the equipment you want added by a local group, or even doing it yourself. There's not too much about, for example, a Sportsmobile Sprinter that departs much from standard RV conversion practice.
2007/2012 custom Jeep Rubicon expedition motorhome
2004 Jeep Grand Cherokee
2006 Honda PS250 Big Ruckus Expedition Scooter
1996/2002 Honda XR600R highly-modded