I haven't taken the time to read all 18 pages of this thread, so forgive me if anything I say has already been stated...
Just saw the Model X pics today, and I have to say the Falcon doors are ridiculous. I can't imagine they will make it to production. I also can't see how having the door fold midway takes any more than about a few inches off of the overall opened height. What it will do is make it much easier to hit your head on the opened door when getting in or out. Compare a picture of an opened SLS door versus this thing and tell me which gives you more clearance. And even that car takes some learning to get in or out of without hitting your head (I've read).
I understand that the bifold theory is to provide a smaller swing arc, but really even considering such a design element on this type of vehicle is stupid. Also consider that an SUV is going to get use in the type of weather that will have rain and slush and whatnot dripping down off of the open door and through the bifold crease onto whomever exits or enters the rear seat area.
Sorry but this door design is stupid, frivolous and unnecessary. It's not a two-seat limited use exotic. But if the intent was to get people's attention, mission accomplished. Which is why I believe they won't be on the production vehicle.
If they're such a great idea, how come the front doors don't open the same way?