No, the photo below is not some abstract, out of focus shot I was taking. It is a high contrast image from a test of the sensor in my Nikon D600 to see if the dust problem had been fixed since I sent the camera in to Nikon last May.
Apparently, the problem has not been corrected, as can be seen by all the spotting on the left side of the image shot at f/8. So back the camera goes to Nikon. I wonder if they'll ever find a permanent fix for this problem.