The Nautilus 1529-2B silent case uses a standard case with a massive heatsink fueled by 6 heatpipes locked directly onto the Intel Pentium4 processor sitting below. The massive heatsink at the top of the case is cooled passively, and silently. A passive powersupply is cooled in a similar fashion by an external set of heatsink fins. Best bet that this silent case costs a small fortune, but it is one of the more radical designs to have surfaced recently, and I'd wager that silent computing like this will interest more than a few people. Silent hardware.de has the full review in german.