Low-Profile Firewalls?

rhyder asks: "I have seen articles on Low Power Computers , and articles on Cool Cases, and a few on Very Small Servers. What I would like to do is use a generic Pentium-Class to Pentium II Motherboard inside a small case with a power supply enough for 1 drive and a single CPU. My intention is to build a box which will run the NetBSD-I386 Firewall Project . Check it out, it is a remarkable free firewall. I already have enough juice polluting the atmosphere, and I would like to keep it to a minimum with this and future projects. Where can I find either slim X86 Clients or cases which meet the above description, and of course, get the best value for the $$$?" We've discussed firewall appliances before, but I think size and power consumption were never really discussed.