Did the Beatles ever record demos of their unreleased songs, the ones they gave away? And if so, where can I find them?

According to the Anthology book, the Beatles detto they made demos of everything including songs they gave away, some ended up on the Anthology cds'. As for anymore releases I heard a rumor that Paul wanted to release più songs but I'm really not sure what's happening with that. te know how mela, apple can be. But one can hope :)