Here is another Mad Professor pedal - it's a derivative of a Big Muff classic circuit. Check out those fet clippers in there. This thing can scream! Here is a you tube demo of the thing: http://www.youtube.com/watch?v=GaUfuqw_8rA
Here is the schematic which was, once again (and as always), produced by the freestompboxes forum. Special thanks to ibodog2!
Here's a link to the Mad Professor Website. Here is a youtube video of the fuzz in action;