Look for something propane.
Have you ever seen those patio heaters- looks sort-a-like a small street lamp? Holds a propane tank in its base. There is a table top version- might be just what you're looking for.
I have used with a little success a propane heater thats the size of a large lunch box. It uses those small propane tanks (like Coleman stove). I don't remember the manufacturer but it came with a conversion kit so it could run off the large propane tank.