I compiled and typeset a hymnal of over 800 hymns using Lilypond, SQLite and Scribus, and the ability to automate the rough setup with Python scripts and then polish the layout by hand saved me probably a year's work. I would absolutely use Scribus if I ever again launched into such an impossibly huge project. It was a great experience, and the result was all I could have hoped.
Ha, I did a (much smaller) project combining Lilypond and Scribus as well. My patch for this (https://bugs.scribus.net/view.php?id=14723) is still stuck in limbo, doesn't look like they are going to apply it any time soon.
In what format did you embed the Lilypond output? I tried it first as EPS, but the print result was really disappointing because Scribus (at the time at least) rasterised EPS instead of actually embedding the vector graphics.
I'm honestly not quite sure what you're asking; there were a few (almost literally) stereotyped page layouts, which I was able to fill from a database, setting typefaces and sizes. That way, I got pages with the layout, tune image, and text, and I only had to adjust hyphenation to my liking and slug the text to fit the columns nicely.
Very interesting. I had thought of going that route when thinking of compiling a songbook, but wondered if simply going with LaTeX, would be better. Anyway, my project never materialized.
From what I've read, the python scripting is very empowering... I'm curious to learn more details about how you got this project done. You can private message me if you prefer.