Suggestions for Coax - Ethernet Solution?

I posted this to slashdot too, but thought that HN might come through for me first.

I just moved from a house with Cat5e wiring to a house with.. A whole bunch of coax cables. Like, my living room has five coax cables coming out of a hole in the wall. All of them go back up to my attic.

The house is big, (and I like it, thank you), but I have realized that our digital usage pattern (media server + squeezeboxes + remote time machine backups to a linux box) will not work without wiring. I am currently bridging some old Linksys WRT54Gs to the right places, but of course, that slows everything down.

This got me thinking: 100mb ethernet is four wires, yes? And I have four wires for every two coax cables. What about a two coax-head -> ethernet jack setup? Has anyone done this before? Searching online only gives me $100+ coax<->ethernet transceiver type boxes. At that price, a HomePNY system would make more sense.

I'm willing to solder if I have to, but I first wanted to get holes shot in this, if there are any.