Firegirl-
My trench smoker is really very simple.
I have a bullet-type upright electric smoker, but it cooks the food, and I wanted the ability to cold smoke. On a sloping hill in my yard, I dug a 6 foot long trench, deep and wide enough to hold the stove pipe. The hill helps with the draw for the smoke. At the uphill side, I put a 90 degree elbow which directs the smoke up into the smoke chamber. I use the barrel from my smoker which already has the racks, etc. I left some loose dirt around the edges of the hole it sits over, which helps seal it at the ground level. Covered the length of pipe with dirt, which helps cool the smoke.
for the firebox at the lower end, I dug a hole about 2X2X2, and lined it with some old bricks and flat rocks. While smoking, I cover the firepit with a piece of sheet metal to keep the fire low and control draft. I can slide it back and forth, or raise it up with bricks if I want to increase the draft.
It was cheap, low tech, and it works! I took pictures, have them somewhere, but I've never gotten good at posting them on here.
It's based on this drawing:
http://www.wedlinydomowe.com/smokehouse-metal.htm
