This is really amazing. After being used to custom XML tags in Android, I so wanted to build custom HTML tags for web apps. This is exactly what I wanted!
You should be able to use this as a standard soon, X-Tag has helped inform the W3 spec. I've been working with Dimitri Glazkov (the W3 draft author) over the last 2 months. We reached initial agreement as a group that the standard, imperative JS DOM API should be "document.register" in the style of X-Tag's "xtag.register" (specs can change though, of course).
This looks extremely promising. Thanks for the great work.