Very widely. My old road-warrior P-bass has one... I added it in the 90's sometime while it was my main gigging bass. I never knew Mission Control had one - although it appears to have been added later since the older pics show a handmade Alembic-style bridge. The last pic marked Grateful-Dead-Photos.com shows a different tailpiece added below the Badass bridge... not sure what is going on there, it's unusual-looking. Almost like fine-tuners but I only see three items toward the butt end of the bass.
And some shots of the inside. Yeah... I think I'll stick with commercially-available preamps, thanks!
To answer my own question above, a user at Alembic.com quotes Mica in saying that the Osage Orange wood rejected the glue and the neck de-laminated. So I suppose that is what happened to it. Also speculation is that the bass was 32" scale, in between standard the 34" of a Fender and most basses, but longer than the 30.5" of a Starfire or EB3.