Jesper - thanks for sharing this plug-in - awesome!
Installing it and had a couple of ideas which no doubt you've already thought about but anyway...
The ability to drag and drop or some way to order the new buttons within the plugin admin would make smooth the process of re-sorting as more buttons are added.
Similar to above but probably not easily achievable - the ability to choose new button placement within all of the existing buttons.
But mainly thanks again for making a nice simple plug-in that works :)