Exactly the same case for me. (32Gb wifi white rMini)
Got 3 yellowish rMini in a row in the same AS in Paris.
First one was almost yellow over all screen, with a wider yellow tint on the left side. (DLXLL)
The second one has 1st 1/3 bottom part of the screen yellow (DLXLN)
The same day I've tried to exchange this second one cheking directly in the store. Unfortunately, it was exactly the same than my second one ... but worse (Bottom 1/3 part of the screen was yellow, even more colored). (DLXLL).
The guy immediatly saw it at the welcome grey screen before initial configuration.
I kept the second one, waiting to exchange it later. We commonly decided with the apple store guys (who where seeing the default like me) that this was no use to check for other units to have another defect.
This was quite annoying because it gives you the impression
First : to use a lot of units and to prevent others to pick one ; stocks seems to be very low and you need to reserve first (that what I've done 3 times to have the chance to try/exchange another unit).
Second : to be very picky (that's what I'm not really usually)
Note that all demo units (16gb wifi white) were quite good with DLXK or DLXLK don't remember exactly.
I don't really care about gamut, i'd only like to have a plain uniform white screen.
Do you have any idea of what that could be ?