The Clutch from Acme Made is a MacBook Pro 13" or MacBook Air 13" briefcase that has a slick leather look. It is a rectangular style bag that looks professional, but is very lightweight (weight is not specified).
This 14.9" by 10.4" bag has a flap that folders over the opening, and uses Velcro to secure the flap. A 3-inch tab on both sides of the inside flap secure to 1.5" tabs