According to Ian's proposal, Mesa 7.7 would be released just in time for Christmas, on the 21st of December. The first release candidate would come at the end of November (on the 30th) followed by two more RCs before the middle of December. At the same time as the Mesa 7.7.0 release would also be the release of Mesa 7.6.1, which would provide stabilization and bug-fixes atop the 7.6 branch.
This Mesa 7.7 release schedule proposal can be found on the Mesa3D development list. Mesa 7.7 should be carrying improved support for ATI R600/700 3D support (hopefully by default), more Gallium3D work, and various other improvements to the hardware drivers.