inspiring @darkpandora
I'm currently researching cooling solutions for my rig:
http://www.anty.info/wp-content/uploads/2011/06/miner1-topview.jpg
That's the temporary solution:
http://www.anty.info/wp-content/uploads/2011/06/miner1-temp-cooling.jpg
Not very good looking, but the trash bag cools about 10°C more than the bag-less version.

I blogged some more information about this rig on anty.info.