Currently running an OpenBSD box as firewall on an old slow desktop box that's very noisy. Thinking of changing to mini-itx format.
Note - I'm intending to use the fanless Eden CPU rather than the C3 fanned CPU. The box has a small fan - but - if this is noisy I can replace this with a quiet fan.
Then all I need is a 256Mb DDR and a CF card - and since the card will be read-only - doesn't even have to be fast.
Thanks to Marius at Conduct for all his advice on this project :-)
Update 12/01 - parts ordered Update 13/01 - parts arrived - and that was with 48 hour delivery! Very good status e-mails from LinITX too.