I think, that, I shouldn'T participate in rumor mongering but...
I'm gonna !
I think the big notes are the lack of the screw drive, and the possible lack of a mirror.
While your d700 comparison has a couple faults, do look at the shape of the red cross section, it's rather different.
I am going to guess, that we can't conclude anything about the scale of the two cameras... Assuming the actual body of the other camera is much larger, the sensor/mount could just be proportionally larger.
I would guess that the lack of a mirror, doesn'T really point to an SLR, even one with a live viewfinder --- I am guessing this will be a rangefinder model. But hey, it's just a guess
Knowing japanese, big, okii in this case definitely means large or big, and not "great". It's possible that the announcement itself will be big, or the camera, or the sensor... It's also a very high context culture, so we could equate that with number of pixels. It could just as easily mean that it's a big step for nikon. From the imagery, we know that It is certainly related to a new camera.
But hey, we'll find out eventually. I'm not worried about it, I've got the camera of my dreams =D
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A poor photographer blames his tools.