Ok, I am now intrigued by this whole thing. As far as I can tell, the remastered Fantasy CD still has only 6 tracks. I can't tell from the description whether it still has the Mingus overdubs or not.
The Jazz Factory claims to have removed overdubs and has 14 tracks. It came out around 2004.
There is something called Jazz at Massey Hall from 101 Distribution with 15 tracks, which came out in 2007 (so maybe they ripped off Jazz Factory?). It also claims to have removed the overdubs.
So I guess I am baffled as to where these PD labels could have come up with a way to get at the original tapes. What is the official release? And why can't I seem to find any "legit" release with more than 6 tracks?
The original release of the non-overdubbed tracks was on this box: