I've just been to the IBC here in Amsterdam and there was a demonstration of Ultra HD which is made by a couple of Japanese companies.
They have designed and build a complete system from camera to projector/flat screen, including recording, broadcasting over fiber using Internet protocols, compression and video scalers.
For the demonstration they had the complete setup running in Amsterdam, a camera on the roof of the building, feeding live to a small theater. The demonstration also included a 14 minute demo of footage from different parts of the world. The theater was run at full resolution and full audio.
At an other places at the conference there was a smaller playback setup with flat panel display, that included a downscaler as the flat panel could not match the resolution of Ultra HD.
Now for the specs:
22.2 channel surround sound.
Oh and the image quality was not really something you can put into words.