I remember an attempt to write operating system in Python primarily, it was called "unununium", apparently the project died, but the site is still up http://unununium.org, though it now talks about ASM, not Python.

A quick google finds this post mentioning a release http://objectmix.com/python/179041-unununium-os-0-1-rc2-rele...

"implemented features include a fully functional Python interpreter, floppy, ATA, and ext2 drivers written entirely in Python."

Would love to find source code for that actually.