are you sure it's overheating and not just sucking in some other way?
heh, my router is a 486dx2/66, overclocked to 80mhz. it has 32mb ram (i think) on 30pin simms. now, since i haven't had it open in about a thousand days, i can't verify this. i never took a picture of the inside.
it runs freebsd 4.1 with a few patches.
but it works, consistently, and i don't complain.
~ dan ~