YouTube announced support for 4K videos:
Today at the VidCon 2010 conference, we announced support for videos shot in 4K (a reference resolution of 4096 x 3072), meaning that now we support original video resolution from 360p all the way up to 4096p. To give some perspective on the size of 4K, the ideal screen size for a 4K video is 25 feet; IMAX movies are projected throughtwo 2k resolution projectors.
My gawd, if you're struggling with 1080p now...
