Originally Posted by Worldwalker
1. "paper" as a format option. A lot of us have hybrid collections, after all.
2. An easy way to import a text file of ISBNs and generate empty books for each of them, or add "paper" as a format if they already exist.
As already suggested, tag every book with a 'paper' tag once you've got them all in Calibre.
If you have a list of all ISBNs in text format just use a macro or something else to put the following in front of the ISBN:
calibredb add -e -i ISBNnr
Save this file as a .bat file and execute it. If you've done everything allright you'll end up with all your books in Calibre, then just select all and Add MetaData.