Stupid Comcast web email won't populate your previous message.....

Anyway, I think you would be better off going the PC route.
Smoothwall v3.0 will support you just fine, and you can always yank a micro-ATX board out of a large case and drop it into something smaller.

I'm using this case for my Smoothwall with an old HP VL400 motherboard inside:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811190005

1Gig processor with 512Meg of RAM and an on-board 3Com NIC with two extra 3Com NICs.
Internal, external, and DMZ. Works great.

I use a Netgear wireless router set up as an access point (static IP, DHCP turned off) for wireless.

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Todd Young