For those who might be curious:
Here is a video with Fuchs explaining the background of his Overdrive Supreme off of the Dumble and demonstrating how amazingly subtle changes in the settings create huge tonal variation in the amp. In the first part he discusses how he started modeling his amps after Dumbles and around 9 minutes in he starts showing how responsive the tone, drive and reverb adjustments are.
http://youtu.be/iOEvd3T7Mjg
Here is an article on the Dumble that mentions George Gruhn selling one to Eric Clapton for $70,000:
The Find: 1991 Dumble Overdrive Special « Guitar Aficionado
Enjoy!