Nice except....this basically takes the stock image and halves it correct? For stills this wouldn't be that big a deal, but for video it is. Especially since it makes the video into a square instead of 16:9.

What about mounting the adapter up and down instead of horizontal? That way, for video, you can have a more letter boxed image and if you shoot with a 4K capable camera something around 2K. This would be the cheapest stereoscopic 2K rig if it could do that, no?

Forgive the crudeness of the crop, the left pic is stock horizontal, the right is up and down. I know 4k would give you plenty of crop space even stock, but up and down or vertical mounting would give you a lot more room to play with.

Then there's the possibility of mounting a 2x anamorphic and keeping the stock mounting or, getting even more room to play with by vertically mounting it.

Of course you can't use it in up-down direction, except if you would watch it with your eyes aligned vertically. Watching horizontally would not give you 3D. Believe me. As already mentined, if using 4K video, and cropping vertically (to remain 16:9 ratio), you still have almost HD 3d resolution (you will need to crop out some of the central part of the picture, additionally). On the other hand the separation of the mirrors will let you take pictures of the subjects which are more than about 5 meters away if you don't want to have exaggerated stereo depth. Have made some pictures with Kula about 16 months ago during ISU World Congress in Ljubljana.

Not easy with anamorphic, except if you have a relatively narrow field of view anamorphic lenses. I think that with Kula you can use 50mm or higher lenses (35mm equivalent) - give or take. With wider lenses you will have to cut out part of the picture, so no gain. Anyway, this is one of the easiest ways to make 3D pictures and videos. Currently, I am using synchronised pair of GH4 in UHD mode to make UHD 3D videos. The quality is excellent, but I have still ordered Kula just for fun.