I'm wondering if the clients will allow you to select any server or if you have to rebuild the apps just to do that. Never used Wired, but I am very interested.
One of the details we haven't quite settled on yet. Safe to assume that once all of the server code is open then at first you'd need to roll your own apps pointing to the right server.
Since a lot of the interest for self hosting comes from companies then a nicely packaged version is somewhere in the future.