I've already got a gas grill. It works fine. Seemed like a larger container than necessary to smoke foods efficiently, and sometimes I have an afternoon to spend on the porch with charcoal, applewood, beer and a book.
To make a smaller oven for smoking, I bought two stainless steel chafing dishes from the local catering supply store. A small wire cooling rack fits nicely to hold whatever you are smoking. Cast iron fire box is on the left.
Pre-lit charcoal briquettes and wood are placed in the firebox:
Soon to be dinner is seasoned with some dry-rub. There is foil covering the wood chunk to prevent flames:
A lid made from the other chafing dish, the same size. Two L-brackets and wood from an old broom make the handle. Offset a little for circulation:
Added another wood chunk. Now we're cooking:
A few hours later. Smoker temp just above 200 and meat temp around 140.
The inside is a nice salmon-color and much of the fat is rendered away by the smoking :
