Updates:
Owner: ---
Comment #11 on issue 216 by [email protected]: Enhancement: the ability to
change staff line spacing inside a \layout{} block
http://code.google.com/p/lilypond/issues/detail?id=216
git grep output-scale
will apparently deliver the contexts that need working on. It seems
problematic that both the font setup as well as the scm/framework-*
components apparently rely on a document-wide setting of output-scale.
This would appear to require more focused work for fixing than I guessed
initially, so I am removing myself from ownership, having other things to
work on right now before I lose focus.