We have for quite some time talked about using Lilypond for embedded music markup. There is a real need. At present, those music articles that have music notation in them are using .png files. There is no effective means of editing these files, and many music editors lack the technical facility to install lilypond, run it, and upload the png. Lilypond is the obvious choice, for us, for music notation, because it has the widest following of any of the GPL'ed notation programs.
I see that Lilypond 2.4.0 is out.
It purports, at least, to have a safe mode for use in web servers. This has been one of the objections to using it here in the past.
I am willing to do some of the work on this. I have used lilypond for a number of projects and am familiar with it, and have a local wp mirror.
Any interest?
UninvitedCompany