The official policy is 30 days in the event of a product refresh, per two managers at my local Apple Store.
I recently exchanged my 2010 MBP 13" for the 2011 after 34 days.
why would you even suggest this? after the return period is over, no one is obligated to do anything.
Because, as I said, I've seen numerous posts like the one quoted above yours scattered throughout the forum since Thursday.