Compact Flash Linux Project (Cflinux) is a Linux distribution designed to run on a compact flash card in read-only mode. It is as small as possible, and currently needs around 14 MB. It includes OpenSSH, quagga, iptables, hostap, madwifi, wireless-tools, pppoe, tcpdump, bridge-utils, and more.
Marc Abramowitz
OpenBSD is better suited for compact flash-based firewalls, just needs some work on it with crunchgen and cutting out things you may not want liked bind, sendmail and apache.
hahahah,
now i can install a little firewall on my digital camera!
-clay