I took a lot of liberties, let me know if I crossed any boundary.
I created an organization called ESOUI at GitHub, there I created a repo with the source code of the game UI (the official one) and proceeded to invite a bunch of fellas of this forum I found at GitHub and also created a Gitter (chat room for the repository).
There we can talk in real-time about add-on development and whatnot. It's public and it's free.
Also you'll be able to see what changes in the UI code whenever we get a new patch.