Seconded on the Dinosaur Jr, one of the reasons I prefer Fuzz, another being the Smashing Pumpkins' second album, Siamese Dream.
It's because of that I own more than one Big Muff (and the fact I've managed to break a couple over the years), trying to get close to the sound Billy Corgan got back then. Then I stumbled across youtube demos of Pedals by Devi Ever, Such as the Rocket. That thing does a fuzz close to the Big Muff kinda stuff and more lo-fi/scrambled tones. Tremendous stuff if you want some really "out there" fuzz. Expensive, but you tend to pay more for hand made "boutique" stuff.
I think I like the Devi Ever stuff because, unlike other boutique pedals and such, these aren't "nice" sounds. I find a lot of boutique fuzz pedals (especially Big Muff Clones and the like) are a bit too refined and almost made to sound more "tasteful", and thus take some of the character out of it.
wow, someone that WANTS a more 'out there' Big Muff. I'd say you're in the minority there mate, but if thats what floats yer boat, great. looking at the schematic of a Big Muff, you'll see that its almost modular by design - they're just taken the same gain stage and put three (if memory serves me right) in series for mondo-fuzz. If you wanted to go even more insane, you could build one with four or even five gain stages, though I'm not sure how useful that would be in practice.
Haha, in truth, I find most of the higher settings on the Rocket less usable, probably good for soloing. The lower gain settings (which aren't particularly "low gain" it has to be said), make for great rhythm fuzz tones (good Siamese Dream style tones), and some cool ocatve stuff with the 2nd fuzz engaged (again, not really for chords, great for leads though).
Here's probably the most out there pedal Devi Ever's made: The Truly Beautiful Disaster:
http://www.youtube.com/watch?v=GnZ_pvI6590Been discontinued a while, but there are a few more being made. Expensive though, and not many song applications, I imagine. Not for your more "trad" music styles, anyway.
I believe your right about the Big Muff circuit - 3 gain stages, been like that since the first "triangle" version, apart from the version 4 "Op Amp" version.