Shuttleworth: Unity on Wayland

I don't really see the problem. Most applications are written using a toolkit, thus abstracting out the backend. The toolkits can be made to choose what they render to, so GTK, for example, can be made to render to X if it finds DISPLAY set and to Wayland otherwise. Thus, if you launch a GTK app from an SSH session with X forwarding, it will find DISPLAY set and render, transparently, over the network.