Mesa has had GLES 1.1/2.0 already since since last year through Gallium state trackers. What this means is that Gallium based drivers are capable of providing support GLES support for end users. Now there is also an activity ongoing to get the Mesa GLES1/2 support to work with DRI drivers and along that to expose multiple GL APIs without separate state trackers on Gallium side.
This work on GLES 1.1/2.0 on DRI made by Kristian received good feedback also Gallium driver developer and is now merged to Mesa.
The discussion about classic Mesa vs. Mesa Gallium State Tracker in general has not lately been this productive (see the Mesa thread). Intel guys are clearly wanting to stay with the classic drivers, and whom could actually blame after all the work that Intel has place to get their drivers to perform. Currently Nouveau camp is the only one that is really utilising Gallium3D and the RedHat guys are going to ship the latest free software NVIDIA bits with the upcoming Fedora 13.