If my understanding of the terms is correct, CCQ simply means a reduced amount of training for the convertion, E.G A320-A330/340. To fly both would be a Mixed Fleet qualification, such as our guys flying both A330/A340.
I really don't see it as a shaft, Flash. It would be a nice rating to have (especially if the -800 also covered the -400), and an occastional freight trip would make a nice change.
My main concern would be if we had a fleet of 100+ 777s, and only 10 or 20 747-800s. You would spend a long time never seeing the four-holer, only to be called out on reserve to fly what must be quite a different aeroplane.