iPad Mini Retina with yellow tint
Don't bother getting a replacement, get a refund as it'll likely be the same and you'll see the same issues on their demo units if you have a keen eye like I do.  Detailed reply below...

I have a space grey iPad Mini Retina 32GB WiFi/3G.  I also have the yellow tint on the lower half of the screen by the home button.  I've tried leaving it plugged in and set at 100% brightness for 4 days and the issue persists 6 weeks later.  I went into my local Apple Store and I could see that all the others on display were the same or even worse regardless if they were black or white bezels or what the serial number started with (mine is F4KM...).  It is a production issue that had been around for ages and Apple think it's now good enough for us not to notice but, a lot of us do!  It's not a glue curing issue and will not go away over time.

I've even been to the genius bar and they can't acknowledge (or refuse to) the problem even after showing them photos, a clear white screen and the greyscale test which clearly shows the issue even under the store's lighting.

I think Apple are clearly aware of this problem and just don't want to go through the expense and embarrassment of a recall affecting millions of units as only a few of us can see this widespread problem that appears to affect ALL retina iPads.  However, they will be forced to act once major magazines and consumer media start publishing these problems.