Phoronix: ADWC: A Tiling Window Manager For Wayland
There's now the first tiling manager for Wayland. Called ADWC, this open-source tiling manager can already start applications using XWayland. There's some videos showing off this Weston fork, including the Opera web-browser and KDE's KWrite running on Wayland...
I am not sure, if 0.85 is considered stable or beta. I was cautious here.
I believe Martin Gräßlin's complaint was that there wasn't any release of Wayland, and developing against Wayland master with its constant protocol changes was... challenging. So yes, I think 0.85 would qualify here. It's quite a lot more stable than master.
I don't think 0.85 has officially been called stable / beta / alpha / etc. anywhere, but it's pretty stable.