With a well insulated van it shouldn't take a lot to cool it off. The Colman Mach 3 PS looks to be one of the most efficient air conditioners but it is a little taller. The Webasto look interesting but I couldn't find any outlets in the US.
Do all rv air conditioners continually run the fan?
BabyBuffy, thanks for the link. Gary has done a lot of work on his website and has valuable information. It's his spreadsheet that I have been working with.