Who makes compact backpacks specifically sized for Macbook Air 11/13" So I'm trying to skate this through as on-topic because I'm interested in items specific to the Air 11" or 13", rather than "what's a good laptop case". (I.e. third party hardware specific to Apple products.)

I'm guess a significant portion of those toting an Air bought it for the portability, which of course is immediately made irrelevant by stuffing it in a backpack with an inch of padding designed to hold a 15.4" beast. So my question is who makes a backpack sized to hold an Air without a lot of wasted space? That is, I'm talking about the laptop compartment itself, not the overall size of the bag.
I have a 13" MBA (bought in July 2011). I have the McKlein Montclare 15494 Small Netbook Laptop Case, and I love it! Here's a URL:

http://www.mckleinusa.com/15474S.html

Apologies though - not a backpack, more a messenger bag or briefcase sort of deal.

I own one in black. It exactly fits my 13" MBA, so obviously you'll have a little extra room if you've only got an 11". I like the amount of padding in the bag, and because it's on the thin side, it "encourages" me to keep my junk to a minimum.

FYI, I can slide my iPad 2 in next to my MBA, and that's about exactly how big the padded sleeve part is.