I have made a hot smoker from a garden inncinerator. I welded a couple off brackets to support two shelves and cut and hindged a door. WELDING GALVANISED STEEL IS TOXIC! I cut a hole in the lid and placed an oven thermostat in. I placed two bricks on the inside of the bin floor and lay a sheet of thin steel over the bricks. If you had a gas ring as your heat source you could place the sawdust on tin foil directly on the bin floor with the gas ring underneath. This would create enough heat to hot smoke. A drip tray is required to stop the sawdust from getting contaminated with fat and oil. This could be a simple tin foil tray. You can use a special smoke box for the sawdust or simply wrap in a few sheets of tin foil and pearce several times.
I burnt my bin with a good fire before use. Kieth Erlandson reccomends you run smoke thriugh the bin for at least 12 hours to leave a tar deposit on the inside of the bin to avoid any metal taint.
I will try to show a couple of pictures when I work out how to do it on the forum!!
Hope this helps? don't think i've broke any copyright yet??