I haven't seen anything for Lilypont integration yet, but Urs pointed me towards the "atom" text editor (here:
atom.io), which seems to be developed by the Git people. I've been using it a bit to help with the Lilypond book project, and -- so far -- it seems pretty powerful.
I'm far too inexperienced with text editors to be able to say anything subtantial about it, but it does have the benefit of being open-source and meshing well with git-based workflows (which, as the blog has been discussing, is an interesting direction for Lily).