Going back to earlier this summer, Eric Anholt has been working on Mega drivers for Mesa. In what began an effort to clean-up all of Mesa's symbols being public after Canonical introduced "libdricore" two years prior, Eric came up with the mega drivers idea.
The mega driver idea is about building all of the Mesa classic and Gallium3D drivers together as a single .so shared library file. By building all the drivers together, there's not a public symbol issue and greater compiler optimizations can be applied through link-time optimizations, etc.
This proposed solution would only make driver entry points public, experiences no performance loss, uses less disk space, and there's the compiler benefits of building all the drivers together with Mesa core.
Issues that Eric has to work through now deal with multiple drivers exposing the same global symbol names and some other internal infrastructure issues pertaining to the change with each of the drivers.
More details can be found from the PDF slides offered by Anholt.