There have been a few bay windows converted to rotary power here in
Australia.  From what I understand it isn't the best engine for a van.  The
one person that I know that has run a rotary powered van, a 1980's Mazda,
said that it used way too much fuel, and his other car was a 351 powered
F100, overheated the oil and water and would die when ever the van was
loaded.  And he couldn't comment on durability as he pulled the engine out
after a short time.  Granted it was only a 12A.  Rotaries only belong in
small , light weight cars, not vans or wagons.  Do a search for Mazda
Roadpacer or Rotary Parkway for an idea what a rotary powered heavier
vehicle is like.
Ian Anderson