My Blue one that i bought in Dec 09 has started to go the same way, there is a blemish in the centre of the back and the edges are all wrinkling as well. Unfortunately for me to return mine is a bit of an issue as I live in Australia.
I actually bought 6 of them at the same time for friends and Family, as far as i know mine is the only one going wrinkly. Interestingly enough it's also the only one with a lighter creamy coloured inside material for the hard case,the others are all a darker Grey colour. I remember reading on one of the other paint problem threads that something to do with the paint not being dry and some sort of a reaction with the leather of the case was the cause of the problem last time but i thought it had been solved?