I think I have found what I need for video. A nikon with HDMI into a http://atomos.com/ninja/
a monitor like (http://www.tvlogicusa.com/product/product.php?idx=67
), it will all add £2-£3k to the price but will cover what I need.
The D4 with it's three crop factors is another bonus in my eyes.
I've just started constructing a gyro mount after various experiments of configurations, a D4 mounted on the gyro should cover my aerial stills and video needs. I would of liked it to be the D "X" but those crops and hdmi in the Nikon win it for me. I tried both the nikon and Canon at a show, shooting video while waving them around to induce some rolling shutter effect. Viewing on the small camera screens I could net see any.
The 300c is getting good reviews, but I don't see it as a camera that will be around for more than five minutes despite the talked about quality.