If you’re already ok… stretching the rights given to you by you library’s eBook system, it’s actually quite easy to load library books onto Calibre and strip the DRM off them so you can keep them indefinitely.
(Like most DRM hacking, I feel it’s justifiable because I’ve already been granted the right to read the book, I’m just time-shifting when I get to do it.)
If your library can give you the book as an ePub file, then you open it with Adobe Digital Editions, as usual, then find the file and add it to your Calibre library. There’s an easy-to-find Calibre plugin to strip the DRM at that point.
