AMC Installing More than 50 of Sony's 4K Projectors
From the release:
The motion picture industry recently announced that it is working with major cinematographers to start production on 4K originated features, and the industry has accelerated development of 4K cameras in recent months. [Sony VP Gary] Johns said that Sony also intends to build a complete system of digital cinematography production equipment, including 4K acquisition, storage and infrastructure solutions.
But as far as I know, we haven't yet seen any major releases at 4K resolution - only 2K. (But according to Wikipedia, "As of July 2007, there are some cinemas in Singapore showing digital 4K films to public using Sony's CineAlta 4K digital projector.") So it's unclear when these new Sony projectors will have true 4K content to play...