But this already exists, as mentioned in post #3.
You will need a barcode scanner (there is probably an app that will do
) and then simply scan all your paper books into calibre.
Calibre Companion is an Android app written by one of our members, which works with calibre to maintain a catalog of your ebooks. You can easily add a blank TXT format to each of the virtual (paper) book formats, from the Add books toolbar dropdown.
Sync to Calibre Companion (transferring the empty TXT files which don't take up much space) and ou can search in CC with most of the flexibility of calibre itself.