The Durham Crazy Horse - an overdrive/boost/fuzz unit. It's pretty expensive too at $250 for a new one. Here's the description from the Durham website:
"This is, I believe, the most adaptable distortion/fuzz pedal on the market. Definitely not a one trick pony! Though the inspiration for this pedal came from a legendary tone, it’s versatility is endless. The controls required to obtain that classic tone also allow you to get any other tone you may dream up."
And a ProGuitarShop demo video of the Crazy Horse in action:
And a schematic from Phibies:
As you can see it's an opamp gain stage into a fuzz face type circuit. I don't know why they don't use that opamp that's after the first stage to buffer the tone section. Strange that.
Here's a PCB layout from Barcode: http://www.box.com/s/ndfz4e7spslljuuruevj
Here's the freestompboxes.org forum topic for reference: http://www.freestompboxes.org/viewtopic.php?f=7&t=3186