This is a smoker I built a while back. I used a 50 gallon hot water tank for the cooking area. A propane tank for the fire box. Used Harley Davidson pipes for the smoke stacks. I added an electric rotisserie that I bought from Lowes.
It works really well and maintains a constant temperature. I use charcoal for the fuel and add apple or hickory for the smoke flavoring. With thicker meats I burn all wood.