I just picked up this pretty good condition 1D Classic for $250 2 days ago, 78xxx clicks, and acutally put it to use at the club tonight.
Terrible tiny screen. I would say it's almost useless after coming from a Canon XTi. Battery life is also useless. ahaha.
I searched, and it doesn't seem that anyone else has this bar thing at the top of the image. It doesn't seem to be noise banding.
This exact same bar is in EVERY SINGLE IMAGE. It's in every RAW. I save RAW only.
Letting you all know, so you don't ask if it appears in another image.
ISO 1600, F4, 1/5.
Here is the original image in full size.