Alright, I figured out what the "scan lines" are, there is a solid black line of nothing between each horizontal row of pixels, each one of these lines is roughly half as thick as the pixel rows. (and the pixels are rectangular like on the 42inch models) After I figured this out I remembered a CES interview where a Samsung Rep said they were doing this on all their sets to improve the blacks in room lighting, they said that any blank spot between pixels would be "painted" black, what they didn't say was that they were going to add blank spots to achieve this.
(my 42px75 Panasonic plasma has no spacers between the pixels, and I would bet money that none of the previous years of Samsung plasma sets had them either)
Normally I can sit 8.5 feet from a 50inch 720p plasma set to get all signs of screen door effect to vanish, but thanks to these black lines, I have to move to 14.5 feet to get them to vanish. I would guess that roughly 1/3 of the screen is made up of these lines, maybe more.
At least this actually does make the blacks look good in room lighting.
I have no idea what I am going to do at this point as my replacment from Amazon has already been sent out, and there is no way that I will be able to put up with these lines.