XBL 2 is now a candidate recommendation ( the news : http://www.w3.org/News/2007#item46 ).
This is the time to implement it into Gecko ;-)
Taking this since I'm working on implementing XBL2.
However note that this is a HUGE project, there will not be XBL2 support in Firefox anytime soon, not because noone is working on it, but because it is a big spec and we want to implement it right.
But we ARE working on it.
Any news ? Jonas, are you still working on it ?
ditto...any information about status would be helpful. I saw that it's also being implemented in WebKit/Safari but this is the browser that really matters! Thanks!
Any news? :-)