"Modern" Ethernet over coax

So, I've just bought a house. It's reasonably new - built in the early '00s. One of the features that got built in was a cable TV drop in every room. The cabling is gorgeous - there's even a wiring cabinet of sorts in a closet where the cables all tie together to the splitter to the outside line.

Of course, my problem is that I only own the one TV. I do, however, own a few computers. What I would love to be able to do is drop a switch in the wiring closet and run 100/1000BASE-T ethernet over the coax in the walls I wouldn't otherwise be using. My fantasy would be if you could get some kind of adapter-plug-thing that would take a coax plug on one side and a cat5/RJ45 plug on the other.

Had anyone else done this? Any suggestions?

(There are a few other options that suggest themselves - first, I could just use the existing cabling channels and re-run cat5 or 6 through the walls. While tempting, that sounds like more work than I really want to put in, so I'm calling that Plan B. Also, I could just scare up a mess of old 10BASE2 cards and run the house on thinnet, all mid-90s style. While I think I'd get major style points for that, I don't think I can get a 10BASE2 adapter for the new laptop. Also, I have all these super-snazzy gigabit adaptors I'd like to be using. And so forth.)

I really think you should go with plan B, as this'll give a lot less problems later on.

It might take some time to install it, but this is only a one-time installation.

Using standard connectors completely makes it easier to ugrade/expand/repair your network later on.

There are some nice connector shields out there that have coax+ethernet connections, enabling you to simply plug in a standard cable anywhere in the house.

also, if you ever want to sell the house, it is worth more, as it has the cables already ;)

Netgear offer 270Mbps Ethernet-over-coax adapters (MCAB1001) for under $200. They can (apparently) coexist with your cable system (if you have one) and provide a 10/100baseT (RJ45) socket to connect to your LAN/computer.

Not sure what the deal is regarding the advertised 270Mbps transfer speed being limited by the 100bT connection though.

In addition to what others said: TV coax is not the same as 10Base2 coax. The former has an impedance of 75 Ohms (at least in Europe); the latter has 50 Ohms.

There is a trade body Moca which has this page with a number of ethernet to coax bridges on it. I think this is what you want. However most of them don't look like they are retail products at the moment.