I built one
I took an old cd rack, lined it with a dozen or so fans ripped from onld PCs and wired them to a PC PSU.

I've got pics somewhere
( VampireMonkeyOnSpeed a super sexy sexual sex terrorist sex, Fri 26 Jun 2009, 11:32, archived)

Brilliant!

( Major Turd for tonight only, Fri 26 Jun 2009, 11:50, archived)