Its been 70's here and I opened one of the boxes up during the show, it was barely above room temperature. I think the 80+ power supplies make a differnce too. I am using the one RJ used last year, its the Rosewill Green Series 630.
As for the vent holes, I used the mounting tabs for the straps, cut them, and then epoxied them over the vent holes in the top cover.