Introducing my LEGO Parts Guide, which is powered by images exported from LDraw.

[Cam's Bricks]

That is interesting, and it confirms that a specific shape (mould) is not a Q-Part, but rather specific parts in specific colors (aka specific elements) are Q-Parts.

I have not personally confirmed it but I have heard that the LEGO store near the factory in Germany will get Q colors on their PAB wall and then those fine their way on to the market via bricklink. There have also been a couple of those on US PAB walls. I have no idea how you or anyone could reliably track such a thing but I do know that as of a couple years ago, there is a "set" listing for PAB walls and BAM parts to help Bricklink catalog parts that are exclusive to the PAB and BAM areas. 

Anyway just rambling along.