Clutter 1.9.2 was released last week as the first post-1.8 development snapshot for what will eventually become Clutter 1.10. This new version has support for multi-backend builds with the ability to switch back-ends now being moved to run-time. The Clutter back-ends can be switched at run-tune by using an environmental variable (CLUTTER_BACKEND).
A new back-end to the Clutter 1.9/1.10 series is a GDK back-end, which uses the GNOME GDK API for creating drawing surfaces and receiving the windowing system/input events.
There's also improved Windows build support (for Microsoft Visual Studio 9 and Visual Studio 10), hint when ClutterText is in the password mode, ClutterStage has been deprecated, and many bug-fixes are present.
See the mail.gnome.org release announcement for Clutter 1.9.2.
Related to that is also the Cogl 1.9.2 release (its mailing list announcement) and it offers a new Cogl 2.0 API that is currently deemed experimental.