Bookup

Bookup is an opinionated book publishing template based on Bookdown.

It is specially useful for reusing the existing design an workflow across multiple book volumes.

It was conceived as the underlying system used by Projeto Vertigem.

It has lots of conventions and heuristics.

At this point Bookup is not highly customized, and probably will not suit your needs, but still can be used as a reference if you're planning to do something similar.

A sample content is available in the Bookup website.