FALL DRESSING: Kara Ross is treading slowly into apparel with her first custom-made dress, but devotees fear not: It’s still all about the bag. The accessories designer created a one-of-a-kind, hand-felted dress, onto which she sewed more than 4,500 Swarovski crystals in the shape of her signature python Nox bag, complete with its classic hardware and carnelian gemstone. The couture piece, known as the Purse dress, will be featured in the Fifth Avenue window of Henri Bendel from Nov. 3 to 9 and will then travel with Ross to Bergdorf Goodman in New York and Harrods in London, both of which house her jewelry and handbag collections. “It’s funny, it’s whimsical and it was so fun to do,” Ross said. “I’ve been collecting vintage for years and I have this amazing jacket with a faux pocket and I thought, ‘Wouldn’t it be interesting to do something similar?’” Ross recently redesigned her Web site and included a video by Adam McClelland that features her daughter, Avery McCann, as the face of the brand.