I am currently working on parallelizing python as an undergraduate independent study. I plan on first removing the GIL with as little overall effect as possible and then implementing a task-oriented threading API on top, probably based on Stackless (since they already do a great job with concurrency in a single thread).

If you're interested in all the details, I'd be happy to share. I haven't gotten far yet (the semester just started!), but I feel that actually implementing these things would be the best way to get a PEP through.

Justin