-> It seems that 8K 33Mpix for 4K 4:4:4 is enough. http://imgur.com/F8Thxlx.png
4K 3840x2160 4:2:0 video has only 1920x1080 color resolution.
4K 3840x2160 4:2:2 video has only 1920x2160 color resolution.
4K 3840x2160 4:4:4 video has full 3840x2160 color resolution.
-> 4K 4:2:0 = 2K 4:4:4
-> 8K 4:2:0 = 4K 4:4:4
-> 16K 4:2:0 = 8K 4:4:4
4K 3840x2160 4:4:4 monitor has Red:3840x2160, Green:3840x2160, Blue:3840x2160 color resolution.
4K 3840x2160 4:4:4 camera has 50% green, 25% red and 25% blue color pattern.
-> To get "true" 4K 4:4:4 video, you have to have 16K 133Mpix! bayer sensor camera?
Edit: Massive editing.