Hi Urs,
Sorry… Possible miscommunication:
would it be possible (or did anyone already do something like this) to include
whole PDF pages between bookparts?
I'm thinking of a way to combine title pages and/or prefattory matter with
scores and use LaTeX to create the text parts but do it from the LilyPond
compilation.
I do exactly this for my scores.
I *don't* run the final compilation from the Lilypond side: I compile all
Lilypond bookparts first (as separate PDFs, if necessary), and then switch over
to LaTeX (TeXShop) to put together the final document, pulling in the Lilypond
PDFs as appropriate.
Hope that helps,