It fits in the Waterfield (SFbags.com) iPad Wallet, and in the 10-inch Muzetto bag, even with the thickest sleeve case.
This video was made when staff at Waterfield Design asked for a photo of how the 11-incher could fit into the iPad Wallet and Muzetto. I thought a video would give a better feel for it.
They are wonderful bags, by the way, best "look and feel" I ever bought.
Same goes for the 11-inch Airbook: *Nothing* slow about it, full sized keeboard, high-rez screen, but only weighs one kilo. This is a portable like portables should always have been made.