Culturejam took one of these apart over at freestompboxes ages ago, I thought I'd add the project here just to keep things ticking.
Here's the description from the Barber website:
"Extremely versatile, high gain distortion, provides wider range of stellar tones.
From ultra chunky, to scooped and back to thick again.
Toggle switch selects mid range character for three distinct modes.
Sweet and powerful Vintage two band E.Q.
Internal adjustable Bass Boost for powerful sub frequencies.
True bypass footswitch delivers clarity when bypassed.
All hand wired in the USA, traditional award winning Barber layout and wiring.
Cascading FET circuit, with MOSFET distortion for incredibly realistic tube quality sounds. "
Ok, now here's an internal gutshot for you:
And a schematic drawn by Culturejam:
As you can see from the gutshot the build quality is top notch. However I'm not sure what they mean "by cascaded FETs". Hmm. It's basically a Marshall Shredmaster with Mosfet clipping diodes...
It does sound nice though:
Now, what you need to do it go and build a Marshall Shredmaster with switchable diode clipping options..
Here's the freestompboxes.org forum topic for reference: http://freestompboxes.org/viewtopic.php?f=7&t=5592