Sony takes the Noah's Ark approach in its prosumer 3D camcorder, the Handycam HDR-TD10. There's two of everything: two lenses (naturally), two Exmor R sensors, and two image processors.
Though it lacks the ability to remove the dual lens (like Panasonic's approach), you can still opt to shoot in 2D, using only the left lens, and the unit can play back 3D content in 2D by using only the left-side video.
It can do this because Sony uses a proprietary approach called "frame packing." Rather than save a single file with side-by-side left/right frames--which the camcorder also supports--the camcorder uses frame packing to save left and right 1080 video streams independently and renders them in combination upon playback.
You can toggle the 3.5-inch 1.2-megapixel glasses-free 3D display between 3D and 2D modes. While it offers full manual controls in 2D mode, however, 3D is completely automatic.
The lenses deliver a 10x zoom, optically stabilized even in 3D mode. And like most of Sony's higher-end models, it includes 5.1-channel audio, with the new improved speakers and microphone system.
All this can be yours for about $1,500 starting in April.