It seems like a stereo photo application for the stock N900 could be created by adapting the method of the Nokia Panorama - just move the camera to the side, and software determines the correct interocular distance, photo area, and alignment. You could set different interocular distances as options.
It would be useful only for still life photos and action novelties of course.
If int_ua's photo is not a gag, how are the stereo pairs stored and then later viewed?
Edit: it looks like the two camera assemblies are clones, so the photo seems to be of a device which doesn't really exist.