Pyston seems to be catching up to PyPy fairly quickly ...not sure if there is anything transferable to pyjion, but if you haven't done so might be worth checking out.
Also for getting around the GIL, PyParallel seems to have a really interesting (and seemingly successful approach: http://pyparallel.org/
Its being worked on by one of the Guy's at continuum...and It's definitely in continuum's best interest to help python's future so I'm sure they wouldn't mind collab.