Goose ..... you're not too wrong there
I've been looking around for plans too and all i can find are plans to make a built in gas grill.
I have done some of my own cad drawings just to try and work out some of the problems ahead of time.
My plans have changed somewhat because the wife wants a stone outdoor fireplace and since field rock is in abundance around here that is going to be my main material. The smoker is going to be attached to it so i can either preburn in the fireplace or use charcoal. I have everything in my head how i want to do it but can't seem to get it onto paper too well. Just need to start building and will design on the fly.
Whenever this project does start i will be doing lots of pics.
This is a link WD posted. Real interesting reading on airflow patterns through a firebox. Might help out a bit on that part of the design. http://www.wedlinydomowe.com/smokehouse-firebox.htm