Code to support it was lying around for long already, but not controlled by UI nicely.
Now you have in user preferences "System" tab an option to set it.
NOTE:
- it only works saving as User startup.blend, and restart Blender.
- your system should support it, no check for it is visible in UI
- tested only on iMac OSX 10.7
Screenshot:
http://www.blender.org/bf/chinchilla.blend.png