I have been smoking on a charcoal grill for about 5 years. lol I recently decided I was going to build one. Every time I cook something I always have a bunch of people wanting me to cook something for them, but I never can because I have no room on my little charcoal grill I smoke on.
I found a complete set of plans online for a smoker called "Big Pappas 500 Gallon Beast" I then found a 500 gallon propane tank, and a nice tandem axle trailer. Next I went to the local steel broker and bought all of the steel I thought I might need. Since I had actual plans on paper, kinda like a ghetto blueprint, but it was good enough for the steel company to cut out all of the pieces I needed to build the warming cabinet and the fire box.