I found a link to a 4 minute bbq video recorded by Cypress Cajun Smokers from Louisiana on DaveTV this afternoon. It shows several shots of ribs cooking in their good looking vertical smokers.
One unit has a rotisserie and one is a more traditional shelf construction. The video shows several good views of the fire rings being used in the smokers. Both smokers appear to be covered with an outer shell made of wood and appear to be metal on the inside.
Here's another link from DaveTV that displays a 1939 Chevy BBQ Smoker used at the American Royal Barbecue Contest in Kansas City. For all the bbq fans that are also automotive enthusiasts, this one is a must see.
Also, be sure to check out the wood barrel smoker being used at the 2005 American Royal event.