I doubt doing that would help, the room hash is generated from the ip, i know you could enter a noip domain in rcms instead of your actual ip, but the room hash still depends entirely on the ip & port, all putting a no ip domain in would achieve is a mechanism for resolving your ip.. without a completely different chat system, with a different room listing... Winmx can only handle roomlists in the current format after all.. you might be able to make a chat CLIENT where you could manually enter favourites in the format NAME:no-ip domain:port but it would be useless on the server side.
or i could be being an idiot