A quick look at uninterpolated data is interesting, too. On the white flower pot to the left of my original crop we can observe that there is a difference that spans over 4 sensor lines and then starts over. It seems to start very bright and get gradually darker three times and then starts over.
The effect is caused by "N-field readout" (the term "field" comes from Sony CCD product announcement documents) where N is the number of fields specific to the device.
If the camera takes acceptable pictures in total darkness with flash and video mode is OK, then the CCD and its related circuits are probably OK, the shutter flex cable is the usual cause of these symptoms.
edit:
One more thing: heavy overexposure might be the result of the loss of ND filter control (the ND filter wires are on the same flex cable).
