[Stackless] Barriers to getting stackless into Python trunk?

[Jim Kleckner]

Stackless is a very interesting technology that looks like it has survived
a long time and become fairly mature.  It offers some substantial
improvements and a unique computing model to Python.

What are the barriers to getting it integrated into the
main trunk development of Python (and presumably Python 3k) ?

It is not a "library" which would cause Guido to exclude it, but
a core extension of the runtime.

Python 3000 seems like a unique opportunity for converging
and integrating stackless.  Comments?

Jim