Cool box idea.

As for the computer fans... I've been messing around with venting ideas myself and have come up with this.
120mm Fan, 4" ABS coupling. I have some strips of thin sheet metal that I've bent in a way where I can bolt the fan up to the coupling. I used some rubber gaskets and trimmed them so there isn't any gaps between the two. Now you can glue the ABS coupling to ABS pipe and run it how you want to run it. Or you can hook up a dryer vent.
I'd take a picture of it right this minute, but I'm down stairs and the camera is upstairs... and I'm comfy in my chair.