Yes, you can buy the 6239 from a TD. I mentioned this at the end of my OP on page 1 (and also explain where each of the watches in the OP were sourced, and described the shortcomings of the off-the-peg reps you can buy. That was sort of the point of my post, along with the pics). You can get them from Marvellous Replica via the special offer post in M's TD forum section. That's where I get the new ones I've bought. Other TDs are available.
The historical background to the term "cartel" in the rep watch world is interesting to read about - as referenced by the links deadpan has posted above. But generally these days, when the term is used it's in reference to vintage Rolex watches made by JKF or BP, that are available from a number of TDs. I guess it's incorrectly ascribed to these watches/factories, but it's sort of a catch-all shorthand term for them that seems to be widely used round here.
