@doublec: Didn't have a look at the sources. I remember vinced reduced the number of possible randomized IRC channel names for bootstrapping on namecoin. Perhaps we have a similar problem with i0coind. The number of possible IRC channels might be too much for a few nodes on testnet.
I don't bother with 'official' testnets. I create my own isolated test networks by not connecting to irc, dns, etc and manually bring up nodes connected to each other. It makes it easier to control.