AFAIK if you want to clone a pattern with a shortcut you have to be focused on the Pattern Sequencer.
I’d like to be able to do this with the focus on the Pattern Editor. It would make sense, since some similar functionality is already available from there (insert/delete pattern, increse/decrease patt. number).
I just happen to use this often, that’s why. And I have a free key just waiting to be assigned. 
You can do this with clone 1 pattern block sequence found in pattern editor -> pattern sequence.
Wow, thanks! 
Yeah, Ctrl+Alt+Shift+F1 by default.
And now I remember I was actually using this in 1.5 when I was carrying the printed shortcut list with me.
But then I obviously forgot about it and hovering over that button only shows the pattern sequencer shortcut…
Hey, printed shortcuts would be a cute thing to have on the wall, the WIKI as wallpaper. With pictures!
This shortcut was removed, actually. Then re-added. Thank teh lord…
you should already be able to print the shortcuts in a readable way: if you for example open the keybindings.xml file with Internet Explorer, it will be shown in a printer-friendly design because the XML file is associated with a XSLT (stylesheet) file which will render it.