I have once read a review with sound examples of the Fetto Nord+, been absolutely stunned by the dynamic quality of it.
Here's the review (it's in german, but that shouldn't be an issue these days...):
"Himmelstrutz Fetto Nord" - das ist mal ein Name für ein Verzerrerpedal. Ob der Sound ähnlich originell und einzigartig ist, erfahrt ihr hier.
www.bonedo.de
Listen to the "Dyna Pick SG" example on the right (or rather listen to all of them, but that one is pretty stunning IMO).
A mate of mine tried to build the vanilla Fetto Nord (without the boost), based on a circuit on tagboardeffects (IIRC) but it didn't work for whatever reasons, no idea whether he got back to it and fixed it (been ages ago).