I am currently in the process of reviving i0coin. To that end, I need beta testers for the new client. PM if you're interested (and have the i0coin blockchain already).
Also, merged mining support would not be available in the initial release, but the door is open for it to be added later.
You need to use -testnet then so you don't screw up the real net.
Even better would be to help get the merged mining patch to apply cleanly to current bitcoin, so a proper update all the way to recent code can be done.
-MarkM-