Hi there,
A friend of mine on this list pointed me towards this thread because I have been doing a bit of work similar to this.
A few months back I made a little python script that worked as a OSC-Zeroconf server/client. Basically you can set up your patches to send OSC to localhost:10101 and recieve on port 10102 and the script will discover anyone else running the script on the same network and re-send whatever OSC you send to localhost to them. Oh, and it does MIDI too..
You can find out a bit more about it and download it here: http://e-mu.org/?p=6
I haven't looked too far into using pyext to embed it in PD, but it might be an interesting direction to look into.
Cheers, Rob