One air conditioning alternative to the Toyotomi setup for those in
less humid climates is an evaporative unit.  While never blowing nice
cold 50F air, it might work for some and it available as a 12V
portable unit:

http://www.swampy.net/

-Karl
Karl and Kristina Bloss, Trexlertown, PA
'87 GL Weekender  "Beverley"
VW shop list: http://www.enter.net/~bloss/vw/vwshops