I know it's not a van, but there are plenty of ambo fans on here. It's a 4wd ambulance, fresh from the fire district, w/ 5k on a rebuilt motor, and $pendy COT! for $4500!
http://portland.craigslist.org/grg/cto/5617886343.html
The District has declared surplus 1 (one) 1996 Chevy 3500 4X4 Ambulance. New front tires, new distributor, Vortec 454 ci, PW, PL, Auto, A/C, CC, air helper bags, inverter, everything works. 170k on truck, less then 5k on rebuilt motor. Comes with cot and is ready to put in service or turn into a service truck or camper.