Git Notes on Branches

I'm wondering if there is a way to (or a reason that would prevent one from implementing a feature that allows one to) associate a note with a branch, rather than a specific object. It seems like a notes object contains a reference to the object that it annotates:

Annotate 4bd93734af...

Rather than forcing this to be a SHA1, can the same approaches as taken with HEAD be employed? That is, allow it to be either an object ID, or a local branch?

This would essentially define a new use case for notes. Rather than just being used to annotate objects, they could be used to describe a feature branch or a bug fix, for example. Then, when a release is created (from, say, master), a "git branches --merged" will show all merged branches. Assuming the workflow is to develop on well-defined branches, if each of these branches had a description in an attached note, created Release Notes would be a piece of cake. Add a description via "git notes add feat-branch-2" that you want to show up in the Release Notes once the branch is re-integrated.

I see a potential problem when working remotely and trying to push the note to origin, but I don't think its insurmountable.

Thoughts?

Josh