I'll do it.
Looks good, besides on objection:
We have under editor settings the category "margins and caret".
I believe because the changebar *is* a margin the settings option should go there...?!
You are right.
Here's a patched patched patch:
https://apt.jenslody.de/patches/scintilla_changebar_20081120-4.patch.
EDIT: Seems not to work correctly, if checkbox switched (I guess the id got lost while copying), will fix later.
Family needs some time now.