[wlug] The Ars guide to building a Linux router from scratch

What about a MIPS-oriented distro like OpenWRT?

I have never tested OpenWRT. I would think that the strength of openWRT would be in its web interface and it has been customised for specific hardware. Both my embedded devices are capable of running debian and I have no need for a web interface. I think you would use OpenWrt if you already have the hardware for it.