Supposedly, the in-flight fire that claimed the lives of over 300 people onboard a Saudi Arabian L-1011 many years ago, heading from Riyadh to Jeddah, was caused by just what you said--somebody cooking with a campstove or Sterno or something in the middle of the aisle. (That's a persistent rumor, anyway, I'm not sure if it's fact.) The crew detected a fire in an aft cargo area and were then told there was a fire in the rear cabin. The saddest part was that the deaths were preventable--for unknown reasons, the captain ordered the attendants NOT to evacuate the passengers upon landing, and when he did land, he didn't stop immediately on the runway--he taxiied off the runway like normal and didn't shut the engines down for three minutes. Between a lack of knowledge of the L-1011's emergency exits, and the fire, it took firefighters at the airport TWENTY-THREE MINUTES to get inside the cabin after landing. Everybody, including the flight crew, died.
http://en.wikipedia.org/wiki/Saudia_Flight_163
}:-)4
“Each member of the flight crew had a history of learning difficulties. The captain had a record of suboptimal decision making through his career. The First Officer failed his training program, was inexperienced with the L-1011, and did not attempt to assist the captain. The Flight Engineer was thought to be dyslexic and was frequently confusing left and right side.”