I somehow got on Overton's mailing list. They are the all-things-boating outfit. Looking thru their catalog and found a portable air conditioner. Interesting thing about this one is it's designed to sit on top of a 12" X 12" or larger roof hatch. You place it over hatch as needed, totally portable, store it in the garage when not needed. Weighs 68 lbs. The product number is 35258. Not cheap however. $819.99!!
Regards,
Wade