You could get the BB Chord Picker Tool to do that just by adding a drop down with all the keys in it, when a key is selected it will
File > New,
Set selected key,
Insert The Major chord for Major and the Minor chord for Minor.
So if you select Am it will insert Am.
The whole idea of the chord tool is for users to create, upload and share their own actions for BB, this will be easier than wishing and waiting for something that may or may not happen.

To include Mac I have just been looking for a cross platform software like AutoHotKey GUI, at the moment the only one I see is http://shoesrb.com/