The loudest guitar with great tone I've heard was a Busato owned by a forum member here. Romain Vuillemin was playing it when I heard it in 2009.
I think you're referring to Michael Bauer's 50s Busato known as "The Beast." One butt-ugly guitar that sounds absolutely awesome. I told Michael that he has to leave it to me in his will.
Benny
"It's a great feeling to be dealing with material which is better than yourself, that you know you can never live up to."
-- Orson Welles
In the vintage area, a "cheap" guitar that can be really loud if you find a good one, is the Di Mauro "Boogie Woogie" . It has a rather "round" tone so it might not pierce like, say, an Anastasio but volumewise it's quite an astounding instrument.
Comments
"It's a great feeling to be dealing with material which is better than yourself, that you know you can never live up to."
-- Orson Welles