Zack Rusin has pushed the OpenVG state tracker into a branch called openvg-1.0, while it will officially be integrated with Mesa for the Mesa 7.6 release. This state tracker that implements the OpenVG 1.0 specification touches 86 files and adds just under 25,000 lines of code to the Gallium3D code-base.
While this single state tracker is a big chunk of code, any graphics processor driver that implements Gallium3D support is now able to have hardware-accelerated OpenVG support without any changes. Unfortunately, at the moment, this does not mean much. There is a half-working Intel driver built around the Gallium3D architecture, a Cell driver, and an ATI R300 driver in the very early stages, but it will still be a few months before Gallium3D is really usable to normal Linux users.
In a mailing list message, VMware's Zack Rusin mentions that this state tracker is feature-complete with all parts of the OpenVG specification being implemented. Until this code has been merged into the mainline Mesa code-base, it can be found in this branch.
Besides OpenGL and OpenVG state trackers, Tungsten Graphics / VMware has also been working on an OpenCL state tracker along with other Gallium3D improvements like video acceleration (along with generic video decoding) and even 2D support.