I'm just talking about the plan of NHK.
Personally I would totally agree with Ilkka and Øivind.
I'm pretty much satisfied with the SD quality movies rented at iTunes Store viewed on my 19" computer monitor.
I saw a slide show of the images of various Nikon DSLRs, from D200 to D810 at the Nikon Showroom in Shinjuku shown on a 4K display. The "lowly" D200 image looked no inferior to those from D810 in terms of resolution. Yes, 4k is a 8MP image which is still outperformed by the 10MP D200.
So far as the quality of still image on a display is concerned, the bit depth may be more important. I'm not sure if the professional 10bit 4:2:2 is adequate for stills.
And a good thing that is, since the "lowly" D200 is my only DSLR.
I have been looking at the D300/D300s for the better viewfinder, AF, etc. More likely I'd go with the D300s to get away from CF cards and into the more readily available SDs, and for the S model's other upgrades. I don't normally print large enough to require 24-36 MPs. Not only that, but if I move up to a model with more MPs then I would have to look at upgrading a couple of lenses too, plus deal with the larger file sizes.
I've got a pro friend that shoots with 36 MPs, but he prints large, and has work hanging in museums and private collections, while my stuff just generally collects dust!