* Same form factor as current 1 Series
* Full Frame 16MP sensor (end of 1.3 crop cameras)
* ISO 100 to 6400 (expandible 50 and 12800)
* Live View with contrast detection AF and HD Video capture (It is considered this will revolutionise photo journalism and meet growing requirement for web news video and cross media feeds).
* Stills can be grabbed from HD Video capture but only at 2MP resolution.
* 1.3x crop mode with viewfinder masking and reduced size RAW (10MP) with significantly improved buffer for cropped RAW images
* 10 fps, buffer similar for FF images.
You could use the 800mm as a hurl its that big. First I have heard of the 1dmk4 are you sure they wouldnt call it the 1dmk3n? seems like a reaction to the Nikon D3..