IC Bus programming

I'm kicking around the software side of this topic...

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1194762543

I just noticed there's a totally separate forum section for software interfacing vs. hardware.

Basically I'm trying to come up with a long bus (on the order of 10s of meters) that I can use to connect multiple microprocessors.

Thoughts?