Speaking of Wikipedia articles, have you checked out their "book creator" [0], it's a link on the left of every page? It has some significant issues [1] and as of now can't be used to download pdfs, it seemed to use an "Offline Content Generator" [2] that became unrepairable. I wonder if something like Percollate could be used as the backend generator for Wikipedia's book creator?

[0] https://en.wikipedia.org/w/index.php?title=Special:Book&book...

[1] https://www.mediawiki.org/wiki/Reading/Web/PDF_Functionality

[2] https://www.mediawiki.org/wiki/Offline_content_generator