Exactly the same case for me, week 49, very slight yellowish tint but everything else is rock solid. I will be keeping mine as well.I received my week number 49 last week.
There is a SLIGHT yellow tinge on the bottom half, but it's really not that noticeable unless you actually look for it, and it doesn't bother me. Honestly, if I never read about the problem on here, I wouldn't have even noticed. I have had no other issues whatsoever, so I'll deal with the very slight tinge, in order to keep an otherwise perfect machine.
Depending on how busy your local store is and how many of the quad they are selling, they could have models that go back to week 48/49. I wouldn't assume just because week 50's are shipping online that you will get on in the store; you might but it isn't guarenteed.Is week 50 the latest week that is available in stores right now? They get shipments on a daily basis, so I was curious.
Maybe they are testing your machine before they ship it out?I ordered an i5 nov 27. Shipped dec 10. It's a week 48 machine. You'd think that since people have recieved their week 49 iMacs several days ago that I'd either have a newer unit, or would have gotten it a long time ago. Something weird is going on with that....