I can hardly pose as knowledgeable about XUL, having only just recently learned to pronounce it, but I’m happy to learn that the Mozilla project is moving forward with XUL bindings for Python. I prefer the more revolutionary slogan, though: “Breaking the grip JS has on the DOM”. Yes! Cast off the chains!
If you’re not versed in the internals of Mozilla, a good bit of that wiki page will make your eyes glaze over. If you’ve remained conscious, also check out Brendan Eich’s blog posting on the subject and the comments on bug #255942.
Seeing Python code inside CDATA blocks gives me the same kind of queasiness I get from the Python-in-HTML web template languages, though.