Grisman and Jerry Garcia had a Bluegrass group in the early-mid-70's named Old & In The Way, and their debut album was put out on audiophile label Acoustic Disc. It sounds fantastic!
Rounder Records is known for their excellent sounding albums, including those of Tony Rice (he's a great guitarist). So is Sugar Hill Records (the Bluegrass label, not the Hip Hop one ;-), and Chris Hillmans' albums on that label are fantastic!