Last weekend I posted a link in the weekly recap that Nikon D7100 firmware has been decoded by Vitaliy Kiselev who found out that the camera can output LiveView RAW video. At the same time Simeon Pilgrim posted a short video demo of the "Live View Silent Raw" recording on a Nikon D7000 camera:
"So for now it’s truly the raw buffer (the part that’s put in the .NEF but with none of the EXIF data), and it takes a hack to turn on, and I’ve not nailed the FPS, nor do I have a clue how to speed it up, but it’s all very cool.
Form the two test video’s I’ve done, the first took 25 frames in 18 seconds so 1.33 fps, on an Extreme 45MB/s San Disk SD card. The second video with an Extreme Pro 95MB/s San Disk SD card, I got 15 frames in 10 seconds, so 1.5 fps. Not ground breaking stuff, but the code to do this was already present in the D7000 firmware. So making it “better” will take a while."
Keep in mind that if you install custom third party firmware on your camera, it will void your Nikon warranty. The original firmware can usually be restored, you can still brick your camera. Some of the previous firmware modifications included removing the time limit during video recording for the Nikon D3100/D5100/D7000 and an unofficial “StarWars” theme for the D5100.