Well, here's a report: I don't normally connect fuzzes in series, but on an earlier hunch, re-echoed by Mr. Hammer's "double clippers" post, I hooked two FF's together, both set to about the same level and fuzz, and it's
exactly the sound I want. Even at a very moderate volume (I can still hear the telephone ring), it hangs on and on, and chords are still remarkably distinct. Both fuzzes are PNP, one has two "fake" NKT275's, and the other has a 2N5089 driving an AC188. The dual germanium fuzz sounds best first in the signal chain--something about coils driving the germanium sounds sweeter to me. It cleans up surprisingly well with the guitar volume turned down, but the whole mess is a little noisy. That may not pose a problem though, since I'll be too busy sustaining and feeding-back to notice.

Supa Tonebender: Are you guys talking about the Marshall Supa Fuzz found here:
http://fuzzcentral.tripod.com/benderII.html ? (1/3rd of the way down the page) Or are you referring to some other version? I can see how this would certainly provides lots of compressy fuzz with that extra grounded-emitter input stage. That looks like the way to go, or possibly some kind of double Fuzz Face. Siamese Screamer? Bipolar Disorder? Double Trouble? Bearded Hypocrite?
Joe