I found these plans, and I am getting ready to build it:
http://animalscience.uconn.edu/exten...smokehouse.pdf
I think I am going to modify it so it has a two part door (so you can replenish the wood chips w/ out letting all of the heat out), a bottom, and install castor wheels on it to make it portable.
I've seen disagreement, but I will not be using treated lumber or plywood. It will be tongue and groove pine for me.