There was a post a while back on the main blog about someone who successfully managed to hack the D7000 and D5000. Who knows, he might be able to hack the D800 as well. I don't remember the website though but I'm sure you can google it easily or someone else here might be able to point you towards it.

I think the best you are going to get will be the uncompressed HDMI 1080P signal from the camera. There is a big difference between that and a full raw chip feed ala video.

I Imagine that the 4fps raw speed says that that is as fast as the camera is capable of processing the signals from the chip. For what you are asking they would need to be able to output 4 times the amount of data as they do for 1080p... since they aren't selling the camera as having 120 frame 1080 only 60... you can bet that that is the limit for them... so assuming they could rewrite the code in the camera you would likely be looking at a maximum output of 15fps for a 4K camera... in short... the hardware isn't capable regardless of what the software is asking.

Hi everyone,

I was thinking about something. Nikon said that the chip inside the D800 is better that the one in the Alexa.
Do you think that Nikon can realease a firmware that unable to shoot 4K/2K video? Maybe if somebody hack the
camera? Or do you think it's something impossible?