IOSONO is a new technology that allows content creators to virtually place sounds outside, along the boundaries of, or within a listening space. I saw/heard a demo on Tuesday at the L.A. AES meeting. It uses a massive number of speakers (I think our theater had around 61 -- 47 surrounds, 10 fronts, and 4 subs) to distribute its up to 32 channels of content. According to its creators, the system uses wave field synthesis to model sound waves as they would appear after propagating from their sources in the mix (in the case of a film, where the sounds should be in relation to the audience). It's already in use at the Haunted Mansion at Disneyland and the creators hope it will become the next delivery format for feature films.
The audio-only examples I heard were pretty compelling, and the IOSONO mix of the film clip they showed sounded noticeably clearer/cleaner than the 5.1 version (perhaps due to better distribution of content through the increased number of channels).
Still only 3D, though.