I am a big user of Firefox and other Browser Keyboard Shortcuts and of Firefox Keyword Shortcuts, but I don't think keyboard shortcuts would be appropriate even if you could devise a method of invoking them easily. There are severe limitations on adding anything to keyboard shortcuts that is not going to interfere with Firefox and/or other extensions. I would say that any extension that adds more than one meaningful keyboard shortcut is almost certainly going to step on another extension and changing keyboard shortcuts to avoid conflicts is really not enjoyable (keyconfig addon).
If you really want to use Menu (Alt) shortcuts you can use CoLT addon but you would be missing out on what Multiple Tab Handler addon has to offer, which is a choice of a lot of different formats of your own creation (some of mine with examples).
A keyboard shortcut is not really going to gain anything if you are using MTH, because you use the context menu with the mouse and continue to use the mouse to choose between currently active or all of the tabs, then to choose which format you want. In fact it is easier to use then memorizing a complicated series for ALT shortcuts that allows you to stay on the keyboard but only do one tab at a time.
For a lack of 10 points here everyone has to put up with crippled links and more effort on my part in a reply
