That is not the case, contents of /usr/share/X11/xkb/ is a part of a different package (xkb-data-extkbd) which is backported debian xkb-data (v1.8 if memory serves me well). And extkbd just reads the keyboard descriptions from there(to fill in the UI list and to prepare hal script).

What I can think as a solution is to re-package xkd-data from repos (with a name like xkb-data-easydebian), so its content to be put under /.debian/usr/share/X11/xkb/ upon installation. And BTW xkb-data-extkbd makes a backup of /usr/share/X11/xkb/ before overwriting it, one just can untar it in the correct place.

I've used to know the hackery used by bt-hid-scripts, but that was a long time ago . And you are right, too many projects on my side, just cannot participate in this one too