The NVIDIA GeForce GTX 680 was released on March 22 and it most likely supports 1080p60 per eye 3D (also called 1080p60 Frame Packing or 1080p60 Stereoscopic 3D) over HDMI. I say most likely since NVIDIA doesn't exactly make things clear and on the NVIDIA GeForce GTX 680 specification page
it simply lists a "maximum digital resolution" of 2560x1600 and doesn't give any details on 3D output. In contrast the AMD Radeon 7970 specification page
is very clear on those issues.
There is a lot of evidence though that the NVIDIA GeForce GTX 680 is capable of 4K over HDMI. The GeForce GTX 680 whitepaper
says that the display engine was designed for "4k and 3GHz HDMI displays". Also the Zotac press release
for the NVIDIA GeForce GTX 680 states that it "supports 3840 x 2160, or 4K, displays via HDMI 1.4a and DisplayPort 1.2 ports to take gaming beyond HD resolutions" and the Zotac specification sheet
states that the HDMI 1.4a connector is "4K ready" and lists "Quad Full HD (4K)" under the HDTV Ready section. If the NVIDIA GeForce GTX 680 is capable of 4K over HDMI than it almost certainly is capable of 1080p60 per eye 3D over HDMI as well.