The only tube-using gunslinger that I know of doesn't post here anymore: soundhound. He was an early adopter of the Model 950 back in 2002 and helped test the red dot and blue dot revisions that tweaked the analog section, and his system uses actively bi-amped and actively tri-amped speakers driven by an array of tube amps (mostly 5W or 10W amps to drive horns in his Altec Lansing Voice of the Theater speakers). Folks who have heard it say that it's a remarkable sounding system, but it's also a fairly unique system.