A bunch of used copies on amazon for about $11. Also excellent (though the mastering could have been a lot better), and available cheap on Amazon is Waves, from 1978 with Holland, Joe Daly and the great Thurman Barker.
Well, there's also Paragon, on the French Fluid label. I don't think it's been issued on CD, either.
Thanks for the tip---I found a rapidshare (The Quest can be found too, if anyone's interested)...This group means a lot to me because I saw them so many times when I was 18-19 years old...and the reunion a couple of years ago at Columbia.
Sam Rivers/Dave Holland: Duo Vo. 1 on Improvising Artists is a very good one. Rivers plays tenor on one side & soprano on the other. I've never cared for Vol. 2 as much - Rivers on flute and piano - but perhaps that's just me. I do recommend Vol. 1 though.