Zohan, malbers, the cameras you link to do exactly what I proposed, but I did not think that was practical to implement in a camera that would be outdoors year round. These look like they're from the same company, or they are a very standard technology, as the images of the filter system appear to be identical. And for what it's worth, the camera bodies make these look like obsolete models, especially with the huge range of smaller dome cameras that is available now.

I suspect the dome cameras don't have such an actual mechanism. I've watched the images as they switch from day to night and back, and there's no hint of anything mechanical; also, the mechanism would have to be tiny, but yeah, it could be made to fit in there.