Bill Evans - The Secret Sessions
Bill Evans - The Complete 1961 Village Vanguard Sessions
Shelly Manne - At the Black Hawk (five single volumes) and At the Manne-Hole (two single volumes)
(there's a shady box of the Black Hawk, too)
Count Basie - The Complete Roulette Live Recordings (Mosaic)
(okay, that's a mean recommendation, but luck may strike or you may have a thick bank account ...)
Peter Brötzmann Chicago Tentet + 1 - 3 Nights in Oslo
(different line-ups including various combinations of "bands within the band", details here)
Albert Ayler - Holy Ghost
(another big one, not sure of it's price range, you get extended recordings from Seattle)
John Coltrane - Live in Japan
(the 4CD edition)
and I fully endorse a whole lot of the previous recommendations (the other Evans sets, the Jarretts - you might want to throw in the 1973/74 Impulse box, which has lots of extende live material -, Ella in Hollywood, Trane 1961, the Petersons, the Mogie, also the sublime "People Time").