I've got a miniature Stirling on my shelf. It's a two cylinder setup that runs off of two small alcohol lamps (about the equivalent of two candles), and is air

I've got a miniature Stirling on my shelf. It's a two cylinder setup that runs off of two small alcohol lamps (about the equivalent of two candles), and is air cooled. It weighs about a pound (but could probably be lighter). I don't know exactly how much power it puts out, but it's not much - you can stop the flywheel with light finger pressure. More heat would produce more power, but I think pencil sized may be a bit optimistic. I like the idea though.