The dilemma for Canon is that if they make the next 5D much better they will be cutting heavily into sales of their 1 series cameras, it's already happening with the Mark II where a lot of pro are using that camera for portraits and studio work. I would guess that Canon is repositioning the 1Ds, not sure what they are going to do but if it's not Earth shaking I think Canon will see a lot of Pros using the 5D Mk3 and passing on any and all 1 series camera.
If they give the 5D3 the 7D's AF - they will improve the 1D series to level the playing field. I imagine the future 1 series will have even better high ISO capability, an even more advanced AF, and faster FPS. Technology moves fast.


