We use the Oakley vertical bag and an InCase neoprene sleeve.
She travels with it, and the bag works very well for her. One of the pockets holds the SuperDrive, and there is a clip for the lanyard on her 3g USB modem. Plenty of room for all her other junk she travels with.
How do you like the InCase Neoprene? Does it hold the MBA too snugly? Is it easy to carry in the bag, I'd hate to slip out of my hand.