Have you heard of Bludotone Amps? Me neither, until I was checking out Jon Herington's (Steely Dan) guitar rig. He use a Bludotone Bludo-Drive. The amps are about as boutique as you can get since each amp is built specifically for the player.
From their website:
"When you choose a Bludotone you can rest assured that you are not getting any old amp, you are getting an amp that was build JUST FOR YOU! We like to speak to each player, the old fashioned way-over the telephone, before building the amplifier. We ask about your style, Guitars, Choice of speakers (when applicable) and what the "tone you've been hearing in your head" is.
Each amplifier is built one-by-one, by hand, by one person start to finish, and we like to have a hands-on personal connection with the player that is getting the amp, sure this way takes longer, and we can produce fewer amps because of it, but after you get your amp...