MB, I think the shutter movement is actually vertical. Check out this 'movie' of a D3 shutter release (including the mirror flip-up).
There was no flash on the image (I checked the metadata), so flash sync problems couldn't explain it.
I agree that the hood is the most likely cause. Does this lens have Tamron's VC on it? I guess it's unlikely, but I was thinking maybe the vibration compensation could have put the lens's image circle off of the sensor.
I can't see how a bad card could explain it.
Yep you are right, at least on D3 and F4, it is vertical, it is not so on all the Nikons though but on newer ones it seams that it is. Stupid me I never check that my self for many years.
Actually the point behind this is that the mirror and curtain travel in opposite directions reducing vibrations, clever design …