I would think roaming would be trivial. You would just connect to all the wifi points near you and send out the same information to all wifi points. The server would just drop all the redundant packets and send the response to all wifi points and the client would drop all the redundant packets. So in theory, you would pass from wifi point to wifi point seamlessly. Microsoft has been doing research into virtual wifi adapters, which would go a long way into wifi roaming.