Cocoon has based its business around its Grid-It! elastic band accessories, which are available as standalone products and built into various accessories. The latest, currently an Apple Store exclusive, is Slim Backpack ($80).
Designed to hold any current Mac laptop up to a 15” MacBook Pro, the waterproof ballistic nylon bag is attractive enough from the outside, though not terribly different from the pack. It’s the faux suede-lined interior design that makes this one stick out.
Naturally, Slim Backpack has a dedicated, padded pocket for your MacBook, as well as a separate iPad compartment. Zip open the pocket in front of those, though, and you’ll find the Grid-It! system.