I saw a DIY scrubber over at IC that uses the Panasonic WhisperLine fans.
International Cannagraphic Magazine Forums - Panasonic Whisper Fan Carbon Scrubber Tutorial: Quietest most efficient fan ever!

I think I might invest in one and make a scrubber/exhaust with it like that guy did. I'm building my own desk right now so I can learn to build furnature type things, then I am going to build a cabinet for my grow and I will probably measure out a completed carbon scrubber and build a little section just for that.