I caught someone looking at this thread a little while ago, and I'm not sure how I missed it the first time around. Here's my (almost surely incomplete) list, in mostly alphabetical order:

Tom Petty & The Heartbreakers (x2)
Jackson Browne
Blue Oyster Cult (x8)
Dio (x2)
Rush (x5)
AC/DC
Dave Alvin
Tori Amos
Laurie Anderson (x7)
Jeff Beck
Big Star
Norman Blake
Blue Rodeo
Grant Lee Buffalo
Jon Butcher
Camper Van Beethoven (x5)
Cracker (x3)
Counting Crows (x2)
Cheap Trick (x2)
Vic Chesnutt
The Chieftains
Guy Clark (x2)
Slaid Cleaves
Shawn Colvin
Concrete Blonde
Alice Cooper
Evan Dando
Ray Davies
The Derailers
Dr. John
Bob Dylan
Ana Egge
Joe Ely
Fastball
Bela Fleck and The Flecktones
David Gray (x2)
Patty Griffin (x3)
John Wesley Harding
Emmylou Harris
John Hartford
John Hiatt
Will Hoge
The Jayhawks (x3)
Rickie Lee Jones
The Kinks (x2)
Kiss (x2)
Leo Kottke (x4)
Alison Krauss
Little Feat
Los Lobos (x3)
Lyle Lovett
Taj Mahal
Aimee Mann
David Mead
Victor Mecyssne
Mike Watt
The Brain Surgeons
Joni Mitchell
Gary Moore
Van Morrison
The Neville Brothers
Randy Newman
Old Crow Medicine Show
Ozzy Osbourne
Graham Parker
Pink Floyd
The Police
Prince
John Prine
R.E.M.
Bonnie Raitt
Kim Richey
The Rolling Stones (x3)
Michelle Shocked (x4)
The Smithereens (x4)
Matthew Sweet
Richard Thompson (x24)
Violent Femmes (x3)
Stevie Ray Vaughn
Gillian Welch (x6)
Wilco
Lucinda Williams (x4)
Warren Zevon


M22ti mains, EP175 sub, VP150 center, QS4 surrounds