While I often find many of wayland's/weston's new/improved features (compared to X11) to be cool, I've found a good chunk of them to be really gimmicky. This, however is not gimmicky. xephyr and xnest are the closest alternatives and to put it bluntly, they suck. You're better off doing a local VNC, which is a lot more of a pain to set up. It won't surprise me if wayland/weston did a much better job implementing this.
I'm getting pretty excited for the next KDE frameworks, assuming it will properly support wayland right from the start.