My first SP2 had the creaking problem on the left top. Got a replacement because of the firmware issue in december. At first no creaking, now the right top creaks a little bit.
I discovered that the creaking does not come from the display itself - it is the plastic on top where the power button sits. Somehow this piece does not fit perfectly. i realized that - when softly placing my fingernails between that plastic and the screen - the creaking stops.
I managed to slide a piece of paper between it and what can i say - the creaking stopped. I will leave it that way for some days and hope that the plastic itself will maybe be "formed" enough so i can remove the paper again withput this issue reappearing.
Maybe it is the same with the creaking units you all got?
Would appreciate any feedback if someone cares to try that out.
(and sorry if i did not describe my method well enough - english is my second language )
On mine you could physically feel the glass move in... store manager was like geez when he tried it...