It’s been two weeks, and unfortunately the Gmail/Greasemonkey API problem still exists (though hopefully Google will get that sorted out soon!), so Bob T. Monkey has been working overtime to find a workaround. After some exhaustive effort, Bob’s just reported back that the add-on lives once again. Yay!
While I don’t have too many details of what Bob’s done (sometimes it’s best not to question his methods), he tells me that version “14563985″ of Gmail’s code is now supported. He also said to let Chrome users know that the add-on unfortunately won’t work with the current Dev channel version of that browser, so please stick to the Stable (or at least Beta) version if Chrome is your browser of choice.
As always, future updates on the add-on’s availability will be posted here and on the Gmail add-on status page.
Thanks to everyone for your patience!