FYI: I think there is something missing in customize.builtins or metadata.odt directly so that the quick_metadata hack works.
But I still don't think that this is the solution.
Looking into oeb.transform.cover it seems to me that as soon as there is a cover href set in the metadata, the titlepage will be generated. And without insert_cover being executed, there will be no OPF meta cover set to the item that is the cover image. Is this correct?
I see a difference in marking a image as cover in the metadata and adding content to a document.
BTW: I'm just rattling down my thoughts here. Please don't see this as urging you to fix something, I'm happy to do the coding as soon as I'm sure how it is supposed to be
