Resale retailers booming because of Birkin bags' scarce supply

It's the must-have handbag for Hollywood's celebrity set. Gwyneth Paltrow, Sofia Vergara and Julia Roberts can't seem to leave home without it. And those Kardashian women -- has each had the bag surgically connected to her arm? The bag seems as vital to them as air and flashbulbs. The bag is Hermès' Birkin Sellier 40,...