Chris:  I've received several recommendations for a firm located in Bend, Oregon who specializes in vanagon automatic transmission repair and rebuild.  K.C. Martin Transmissions (425) 672-0920.
Larry Chase had good experience with them as have several other list members.  The cost of shipping the transmission to them would have to be considered but you might want to check it out.  I've not had personal experience with them as yet so can't provide a personal recommendation.

I had a rebuild on my last 90 Multivan done by a fellow in Portland, Oregon for $800 last year but ended up having to take it back twice to get things ironed out.  Still had a slow leak when I sold it.

Thanks,
Brent

Brent Weide
Portland, Oregon
http://www.weidefamily.net/vanagon/