Ok, I see what you mean.
I don’t know where book summary is stored. Could be in a EPUB ifself?
I would start copying some book from /data/media/B&N Downloads/Books to SD card and check if you get a summary.
X-ray search – know nothing about it, sorry.
About Archiving - I guess, we supposed to be able to delete a book from nook and be able to download it later again (since B&N have a record that we bought it).
For side loading, we can create Archive folder.
I know, it’s not exactly archiving, but just trying to be helpful…