The KDE LightDM greeter is now up to version 0.1.0, which is now usable enough to make it into the Ubuntu 12.04 repository.
The LightDM KDE 0.1.0 greeter features three QML-based themes, guest log-in support, a KDE system settings module, and "a few bugs (maybe) and design quirks (definitely!)."
There's some screenshots of this LightDM-based KDE greeter within
this announcement blog post.
This release comes after months of
LightDM-KDE being tested and after extensive work on
KDE/Qt-bindings for LightDM were
worked on in months prior. LightDM replaced GDM within
the Ubuntu 11.10 release and continues to serve its role with the forthcoming Ubuntu 12.04.