Black stripes on screen

I have exactly the opposite problem! On a black screen I can see two lighter stripes exactly where yours are. Since the positioning matches perfectly the bottom side of the keyboard and the top side of the trackpad, my bet is that the aluminium edges press on the screen (on mine you can also see tiny scratches when it's off). When I noticed this I bought a screen protector (http://www.radtech.us/Products/NotebookScreenSavrz.aspx), essentially a cloth you put on the keyboard when you close the lid. It seems a design flaw, with the screen being too close to the keyboard, bring it to Apple and see what they say.