There's already initial OpenGL ES 2.0 support for Compiz, but it's not yet been merged upstream. OpenGL ES 2.0 support for KDE's KWin is also being worked on.
The Compiz GLES 2.0 push upstream is expected to take place after the new Compiz shader API is integrated. Support for missing plug-ins also needs to be added along with per-plugin shader support. Clean-ups are also needed and potentially better consolidation between vanilla GL and GL ES code. Build-time support for OpenGL vs. OpenGL ES suppoort was also discussed as well as testing.
On the KDE side, OpenGL ES 2.0 development support is also underway. The Compiz support though is the primary focus within the Ubuntu community since that's the compositing window manager needed for the Unity desktop.
The rest of the notes are on its EtherPad page.
Also this morning an OpenGL ES 2.0 back-end for Cairo was discussed. Already an OpenGL ES back-end for the Cairo library was developed. This GLES back-end is based upon the experimental OpenGL back-end for Wayland. The focus now is on optimizing the OpenGL ES 2.0 back-end for performance and to optimize the ARM drivers for this back-end. Details for that are here.