KDE5 is coming out in June, but initial release will not support Wayland in KWin. But it should come after as an update. I'm not sure about exact schedules though.

See:

* http://techbase.kde.org/Schedules/Plasma/2014.6_Release_Sche...

* http://blog.martin-graesslin.com/blog/2014/03/kde5-and-wayla...