Can I create a custom button in Thunderbird to enable me to copy or move an email to a specific, pre-determined folder with a single click?
I've not yet been able to find an extension that provides buttons for quick filing into folders.
However, you can install the Custom Buttons extension and script functionality to move email into folders of your choice: https://addons.mozilla.org/en-us/thunderbird/addon/custom-buttons/ (I didn't have much luck quickly finding example code to move an email).
However, the Nostalgy extension provides quick filing to folders via keyboard shortcuts: https://addons.mozilla.org/en-US/thunderbird/addon/nostalgy/ (no doubt the quicker of the two).
For those looking for custom button to move folder..
Thunderbird 31 (see bugreport https://bugzilla.mozilla.org/show_bug.cgi?id=1043819#c1):
To extract the URI from a folder, you can just use “Rightclick to a folder > Properties”. There you find the URI in the field address.
Credits goes to the author and commenter @ http://guarly.wordpress.com/2010/04/30/thunderbird-3-and-keyconfig-how-to-move-messages-to-a-folder/
For people who are looking to use this feature to duplicate the Archive feature on google mail accounts, there is an actual "Archive" button available if you right click on a menu bar and then select "customize."