This project may be cool, but it doesn't --- and can't --- make the XBL binding nodes anonymous, which is the single biggest feature of XBL. Without anonymous nodes you lose a lot of the modularity and transparency benefits, and because you smash the original DOM you cripple the ability of the client to manipulate the DOM after the script has been applied.
So what we have here is a DOM preprocessor which uses XBL2 syntax, which does sound cool and useful, but it's not remotely an "implementation of XBL2". The blurb on the project's Web site is very misleading. It's also misleading when people who should know better blog as if the claim was true.