Just received a message from Mozilla indicating that whatmon has been approved. It has taken a while, but at least it is now officially available. It is however, my fault it's taken so long:
In the future, if the only change to your add-on is an update to the maxVersion compatibility, you do not need to upload a new version of your add- on. Simply use the Developer Tools section on AMO to edit your add-on's compatibility - no code changes required!
Interesting to note that whatmon has quite a few downloads to date (21,000 in total). I wouldn't have thought that such a "specialized" add-on would be quite that popular. :-) Anyways, if you don't yet know whatmon, then read about it and get whatmon now.