It's the nicest-looking iPad case we've yet seen, though also one of the most expensive: Vaja's Retro Slim Jacket for Apple iPad ($120) is a classy leather iPad sleeve case with a magnet-locked top flap. It opens to reveal the same accent-colored interior as the front stripe, with a similarly Vaja name-embossed beige layer nearly out of sight below. A silver logo appears on the case's front, with no markings on its back. For the time being, Vaja is…