I've looked at these as well and am really not interested. Next spring I want to get a rib hanging rack for my WSM and try that. I've heard people that hang ribs in a smoker rarely go back to any other way.
Hanging rib racks? Interesting! The restaurant I worked at in high school did exactly that. There was a fairly large cooking pit, enclosed on all sides with clear glass. The ribs were vertically hung on a hook, and traveled around the inside of the smoker on a monorail track system.
Under the ribs was a huge pan of BBQ Beans, catching all of those awesome fat drippings.
I can't hang ribs with my setup, a Kettle and an offset smoker. Using rib racks is what has been done, with good success. I would prefer to have the ribs lie flat on the grill, however.