Here's the skinny on the Kawasaki Vulcan 1700s. The range comprises four motorcycles that share the same motor, chassis and cycle parts.
The Voyager is the top-of-the-line, all-singing-all-dancing model, and it constitutes what Kawasaki is eager to point out as "the first metric, vee-twin, full-dressed touring motorcycle ever." It was also the main focus of development for the range, such that the other Vulcan 1700 models are essentially less-dressed versions of the Voyager. The Voyager boasts a frame-mounted fairing sculpted to incorporate design elements from '60s muscle cars (and also giving a nod to Harley's Road Glide).
The Vulcan Nomad retains the hard bags and touring king-and-queen seat of the Voyager, but loses the top box and fairing. Instead, it has an adjustable windshield with fitted lowers, a tank-mounted instrument panel, and a passenger backrest in place of the top box.