While it’s not a guitar amp, the 50th Anniversary Limited Edition McIntosh MC275 deserves a look just because it’s a tube amp taken to a level not seen too often these days. The MC275 uses 3 12AX7s, 4 12AT7s and 4 KT88 output tubes. For tube hi-fi guys (or gals) I don’t think it gets much better than McIntosh.

From the McIntosh website:
The 50th Anniversary Limited Edition McIntosh MC275 tube power amplifiers combine modern convenience and performance enhancements without altering the sound character that has made it famous for the past 50 years. A very limited quantity of the special 50th Anniversary Limited Edition McIntoshMC275 has been created for only the most discerning of audio connoisseurs. Individuals who are fortunate enough to own this timeless amplifier are certainly amongst the most sophisticated audio enthusiasts globally.
If you haven’t guessed already, McIntosh amps are not cheap. The MC275 goes for about $6500.

McIntosh tube amps are known for a unique technical innovation called a Unity Coupled Circuit. This is a circuit developed by Frank McIntosh that requires specific transformers called trifilar wound output transformers. This design allows the tubes to run cooler and provide greater accuracy in sound reproduction.
McIntosh amplifiers, both tube and transistor models, were used for the PA at Woodstock. They were also used by the Grateful Dead on tour for their “Wall of Sound”. The McIntosh website has a nice presentation about the company’s history here if you’re interested.
