I don't know of a trio, let alone sextet, for you amey. However, I would look towards flutist James Newton as he played with all kinds of ensembles. The problem is that some of his recordings can be very tough to find.
The only cello stuff I've really ever seen was by Ray Brown. I'd imagine with some digging around you might find him playing cello with Ellla, since they were married for a while.
Violin? I still remember the day Stefan Grappelli died, sad to lose such a charasmatic musician. The old Hot Club stuff has really awful SQ, but he does have a much more recent 85th bday concert at Carnegie Hall, with the Rosenberg Trio as the opening act. The Rosenberg brothers were cloned from Django, no doubt about it, freaking shred-mongers. Anyways, Grappelli first learned to play violin in a movie theater!
For male vocalists, Im a little surprised Kurt Elling has not been mentioned. I don't know of any peers.
My favorite insturments? hmrz... today I would say...
Piano
Sax (all of them)
Bass
my favorite jazz musician of all time, period, is Charles Mingus. If only because he is the most contrapuntal jazz musician that I know of. Favorite sax player is tougher, Id probably say Michael Brecker, who I was fortunate to see during a Coltrane tribute with Han****, Patatucci, Hargrove, Blade (one of my favorite drummers) before his unexpected and sad death. He's just ridiculous. Pianist? hmmmrrzz maybe the Duke.
p.s. funny that Herbie Han****'s name is censored...