BlueGangsta, check out her very early 1967-1968 bootlegs, there's a lot of unreleased songs in those. Some of them have surprisingly good audio quality. There's the 1972 b-side to "You turn me on I'm a radio", called "Urge for going", which was released on cd on her "Hits" collection. The "next" album mention in the 1972 Carnegie Hall concert might be about 1972's "For the roses". The Carnegie Hall show took place in february and "For the roses" was released in october, so she probably was talking about the new songs in the show being on that next album. There was talk of a 5 disc box set around 2005. One of those 5 discs was supposed to be a dvd. There were to be alternative takes from the Mingus sessions, as mentioned before, and unreleased songs, especially from the first album sessions because she had already written a lot of songs by that time. She mentioned a song called "Jeremy", and that David Crosby still had some studio tapes from those sessions, where you can also hear the both of them chat. Also, at that time, Joni wanted the liner notes on that box set to be "written by fans", so you were asked to send emails to her official website, detailing why you loved Joni Mitchell's music. Joni was supposed to select her favorites and those were to be the liner notes. Not trying to get picky there but such a box set would have been far more interesting than the "Love has many faces" one. No offense Joni! That being said I'd love to know which ones of her concerts were recorded and not (yet!) released.