Extracting a "score diff" from two [or more] Lilypond sources

[Kieren MacMillan]

Hi all!

Given multiple Lilypond sources, I'm hoping to find a way to output a "diff 
file" describing the musical differences *as would be perceived by a human 
reading the score*. For example, given

    Score #1 = \score { \new Staff << { c'1 c' } >> }

    Score # 2 = \score { \new Staff \new Voice << { c'1*1/2 s2 c''1 } >> }

diff ( Score1 , Score2 ) would say [in effect] "m2: Score #1 has c'1 while 
Score #2 has c''1."

Because coding style, "hacks" (like c'1*1/2 s2), variable/context separation, 
and other code-based differences aren't [directly] relevant, I can't just use 
standard text/diff tools. Is there a way two "music streams" (oof, I'm 
definitely talking out my butt right now!) can be compared in Lilypond and 
some/most/all of the human-perceivable musical differences be automatically 
detected?

Thanks for any brainstorms, ideas, or (dare I dream!?) snippets!
Kieren.