You know, if I hadn't seen evidence of this before, I'd never believe that anyone would go to all the trouble of counterfeiting one of the most common processors ever.
The subject I read about, however, was the SID chip, as used in the Commodore 64. There was a site detailing counterfiet SID chips. In this case, they were simply known defective chips repainted with a different manufacturer code.
Again, IMHO, it seems like an awful lot of work for not much gain... like making counterfeit dimes.
-Ian