Old thread, but I couldn't resist posting up a link to the solution that saved my trip from California to South Carolina. Especially since Amy (the seller) was sweet enough to overnight it to the hotel we were forced to stay in after a heat beating of mid summer in Austin, TX.

http://www.busstuff.net/Pages/ac.aspx

This was so easy to install and is not permanent. We travelled with a 7,000 BTU window ac unit strapped down to the luggage rack of our 1997 EVC. The canvas just lives under our seat when we're not using it. It's the missing link to easily turn the Eurovan Camper into an all-climate camping machine.