PyMite
Here’s a paper from 2003 detailing a Python interpreter for 8-bit architectures:
PyMite is a flyweight Python interpreter written from scratch to execute on 8-bit microcontrollers as well as desktop computers. It is a work-in-progress, but is developed enough to run demonstration programs.
It looks like PyMite is still actively maintained, with a release in September 2006.
More info on PythonInfo.