I understood that ... it is the 8 fps I want with the 2X. I do understand the shuttling around of the bits and that is all the camera can handle and the reason for the 2X. It is essentially 2X (let's say digital zoom) but I like the idea. Best of both worlds. When I shoot for speed, I am using the telephotos (either the 300 f2.8 or the 400 f2.8) . The 600 max aperture of f4 is a killer for me with the greater DOF and loss of low light flexibility especially shooting night high speed sporting events. The 6.8 mps are fine for me especially with good glass.

I've shot the D2X (a friend of mines) and it is flexible. The cropped "image" shows up in the viewfinder and is great for sports since you can see out of frame action which helps anticipate the shot better. The 8 fps virtually assures the best frame possible (soccer excepted due to the speed of the ball).