Like in a microphone? Lol, just kidding. You mean a completely silent case. Yea it's possible, if everything was passively cooled which right now doesn't seen too likely. Zalman's coming out with a nice heatpipe case, but I think, even then, your PSU will have a fan, and in some cases your northbridge for your motherboard. But with this technology I wouldn't be surprised that we can do it in the near future.