XLink and XPointer in JavaScript?

Did anyone ever implement these specs in JavaScript?  I'm considering 
doing so - I have a context in which I can maintain the necessary state 
- but I'd rather not reinvent the wheel if it isn't necessary.

I'm also contemplating writing a CSS selector XPointer scheme for 
registration at:

http://www.w3.org/2005/04/xpointer-schemes/

If anyone's interested in participating in these, let me know!

Thanks,
-- 
Simon St.Laurent
http://simonstl.com/