Very interested as I've had the darker half on the bottom of my tv since shortly after I purchased it. It went away after a few minutes and it became a bigger problem when it stopped going away.
It also developed problem in which it "ghosts" on the top left part of the screen as you are looking at it in that the pictures have "trails." This was the problem that I couldn't live with at all. I finally got in touch with samsung and was disconnected a few times... I was told to call executive account services because my warranty apparently expired which I know it has not.