HDTV has a next generation
Japanese Broadcaster NHK is developing the successor to HDTV called Ultra High Definition. UHDV offers a resolution of 32 million Pixels compared to HDTV's 2 million pixels.
Picture size of 7,680 by 4320 for a 1.77 aspect ratio (AKA 16x9)
So with 4,000 horizontal lines of resolution it blows away current HD.
It will have a refresh rate of 60 Frames per second....