Engadget has a picture of what they are told is a prototype EX3 3D camcorder. They don't have any other information about it.
It's hardly surprising that Sony is up to something like this; I actually thought they might announce something at NAB. At a lecture a couple of months ago, a Sony rep actually talked about a 3D camera they were developing - though he wasn't saying there was any product coming - and he showed a picture, but it wasn't this camera.
Don't forget that the EX3 has a bayonet lens mount; maybe this is a 3D lens unit that simply plugs into the EX3?
[UPDATE] It's surely an early prototype; if Sony was close to a real product, it surely would have been shown at NAB. Also, it's been pointed out that this camera is missing a viewfinder; though a regular viewfinder may not work very well with this.