Yeah, the Dumble thing has become like the Marshall thing, but the price tags are higher. Basically a bunch of folks started cloning stuff from schematics and then adding features or taking it in a slightly different direction or creating minor variations. It is essentially an amp "style" or family at this point.
There's even more mystique since you had the outrageous price tags, low number of physical specmines, and the Dumbles intentionally varied from amp to amp. On top of that, the amps were intentionally obscured (gooped inside) to prevent reverse engineering. Thus you got a bunch of schematics that varied based on the specimen, degoop quality, etc, they were handed down, traded and argued over like ancient Egyptian papyri. It's all quite neat and archaic at the same time. And some of the amps are even good to great sounding.