Since I0Coin supports multi-sig addresses, it looks like it maybe should be able to be supported by the "distributed exchange" system found at

https://github.com/pharesim/HZx

I am not sure whether non-main nodes of the thing just run scripts directly under PHP or require setting up a web-server for the PHP to run under, the idea of having to run a web-server kind of put me of from just setting the thing up and giving it a whirl.

-MarkM-