I just picked this up at my local Apple Store:
Lacoste Sports Messenger Bag. I chose the black straps over the white because I think it'll be easier to maintain as the white which can get dirty quite easily.
Looks like an Apple exclusive (at least the color). Fits the 15" unibody like a glove; very snug and it has a few slots, 2 of which fit the iPhone and iPod classic very snug.
I love it. I'm also a Lacoste fanboy, so this works both ways (Apple & Lacoste).
Interesting. I've never seen a Lacoste item in an Apple Store before.