Recent discussions have brought up the need for a low-BTU heat source that doesn't use a bunch of electricity, is cheap, and most importantly safe.
Here's my idea for heating a small trailer. Take a Dietz kerosene lantern such as the Little Wizard or Jupiter
Build a base to hold it in place, remove the top cap, and then run a small diameter stovepipe from the top right up through the trailer roof.
These lanterns use the "Cold Blast" system of air induction described HERE. It seems that with the stove pipe adding more draft that virtually all the products of combustion would go up the chimmney, even though the lamp isn't a sealed burner.
To be safe I would provide a source of combustion air, a bit of high-point venting, and a carbon monoxide monitor/alarm in the trailer. Obviously the prudent thing would be to test the system while monitoring the CO levels to be sure it's safe. (Kidde Nighthawk Digital)
The Little Wizard generates 1100 BTU/hr, the Jupiter 1400. If you got half that into the trailer it would be a handy bit of heat. To keep it from being too bright you could use a colored glass globe.
I'm thinking of rigging a test chamber in a cardboard box to see if the idea would actually work. I have need for a kerosene lamp and a CO monitor anyhow.