If you deal with 3D Stereo Video sooner or later you will have to find a solution for the HDMI 1.4a problem as of today there are only very little devices available that support it. This format for example used by Blu-Ray 3D or the Sony Playstation to play out 3D video, sends the left above the right eye image in one frame without anamorphic compression.
If your display device does support it or if you have a setup with two video projectors where you need left and right eyes in two separate signals you have to convert somehow. As of today I only know of two devices that are capable of that.
For a conversion to 120Hz stereo this is the Optoma 3D-XL. It converts HDMI 1.4a as well as Side-by-Side stereo video.
For conversion to Side-by-Side and to two separate stereo signals it’s the rather pricy Corio C2-8000 series full fledged seamless switchers from tvone that became available at ISE 2011. I’ve had the chance to test the C2-8110 that comes with 6 HDMI 1.4a capable inputs and two outputs.