i hear you on apple giving you a hard time.
I had a similar experience. My MBP i bought in 10/08 needed a logic board replacement. The guys at the Apple Store in downtown Portland are great.
Anyways, i noticed about a month or 2 ago, that there was some wear on the "palm rest", at the edge of computers' surface. I could understand if it was a year or 2 old, that this is normal wear. But a few months old?
So i made an appointment and they looked at i and told me that it was cosmetic and couldn't do anything about it. There is also a line on the LCD screen from the space bar. The genius told me that some peoples' skin has some kind of affect on the iodized aluminum surface..ie; some peoples' skin is more oily than others, which eats through the surface... and i guess some of the oil got onto the space bar, and thus when i close the lid, it rubs on the screen, which he said is cosmetic as well...
I was kind of mad, as this was brand new and expensive. The irony of this is that there was dust in the screen of my iPhone, which they promptly replaced

i know it is just cosmetic, but still... the screen thing you cannot even see unless you look for it when the screen is black....
good luck with your problem..