Hello there,
I have put together a simple implementation of urdf in Python.
It is available here: http://www.ros.org/wiki/urdfpy

It is not yet in an usable state but to avoid duplicating efforts, I
prefer announcing this early.
This project is not high priority on my TODO list so contributors are
very welcomed :)
The package relies on minidom and the code is really easy to understand.

Best,
-- 
Thomas Moulard