The new Nikon D4 has some amazing capabilities on paper, and by now most people have seen the amazing video by Corey Rich. The video below demonstrates many of the D4's new video features, including using an iPhone or iPad to control the camera, clean HDMI out onto an external recorder, and selecting the crop modes. Nikon really did this one right, but it looks to me as though that the focus tracking makes the aperture breathe, which would make it unusable during recording. See if you can spot where he knocks the camera over by mistake!
Here's a demo of the D4 working with the new WT-5 wireless transmitter and the iPad.