So I sent out my first yellow tinged iMac a week ago. Replacement arrived today. The SECOND I turned on the screen on the brand new machine today, I noticed a problem. There is better color uniformity, and yellowing doesn't seem to be the issue except for this huge horizontal gray band across the bottom that is very prominent. I talked to the Apple Senior engineer who had "never seen this issue before", and was surprised since I had one of the newest serial numbers he has seen (week 10 iMac i7) Attached is the picture I sent to Apple which has earned me an advanced replacement (machine sent to me while I keep the defective one until I receive the new one - then have 10 days to return the old one or I get charged for 2) (Ignore the vertical reflections, the horizontal bar where the dock lies is the issue at hand here) Image is straight from my Canon with no retouching at all.