It will be kind of heavy though. For simple charging of appliances, other projects are very interesting:
http://www.kickstarter.com/projects/ryochijiiwa/bootstrapsol...
http://www.kickstarter.com/projects/davefoster/lilypad-using...
http://www.kickstarter.com/projects/ryochijiiwa/bootstrapsol...
http://www.kickstarter.com/projects/davefoster/lilypad-using...
I'm imagining a sort of pencil-sized Sterling; stick one end in the fire and the other in a cup of cold water. Not reliant on ambient/weather conditions for power.
More heat would produce more power, but I think pencil sized may be a bit optimistic. I like the idea though.