My ac went out so I had to macgiver this shit.
I took an old trunk, like the kind your grandma keeps at the end of her bed and fills it with blankets and stuff. I attached a furnace blower (squirlcage fan) from a fullsized house furnace. I then stuck my 2x milkcrate rigs inside. I have a hole in the opposite end. It pumps so much air its crazy. I put the hole thing out on my porch that is pretty open, lots of windows. Even at 100f outside the hottest card is only 83c and the coldest being 64c.
I'm going to make some custom mounts with 1x1s in the box and put the components directly in the box, this should allow me more cards and more boards. I'm thinking I could put atleast 12-15 video cards in that old trunk and keep them all below 85c at 110f outside.
http://youtu.be/0de0aEpyTJQ