The Puzzle Piece Rated 5 out of 5 stars
Hi Alopepeo. I apologize for writing this here, but you provide no other way of contacting you directly.
I just wanted to mention that my add-on, The Puzzle Piece, also moves the add-on bar to the location bar. This was a feature request by a user, and I did it because I was under the impression that both this and url-addon-bar were no longer being actively developed.
TPP already works in Australis (version 1.2.2 for full compatibility; it's in the queue at the moment awaiting review) and can also toggle autohide without needing another add-on.
Sorry again for writing this here, but I thought you would want to know. :)