Wheels Away (http://www.wheelsaway.com) has posted a video on their web site demoing their carrying cases for iMacs. The “cases on wheels” work with 21.5-inch, 24-inch and even 27-inch models.
Wheels Away cases are waterproof, durable, lightweight, silver, and sleek. The company offers a 30-day warranty. The Wheels Away cases are US$149, $159 and $229, respectively, for the 21.5-inch, 24-inch and 27-inch models.