I thought about the A/C question last year with a customer's westy.  My idea
was to use some PVC piping (square) that is normally used for guttering and
run these from the rear A/C unit up to just behind the driver's head.  You
could paint it to match the interior of the van and terminate it in a vent
that would allow you to control the direction of the air and also the amount.
 I tested this idea last year and it worked excellent.  Haven't had the
chance to perfect this setup yet though.

Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: (856)-765-1583
Fax: (856)-327-2242