With the temps around 20 degrees here in PA, I am trying to find a plug-in thermos that I could keep in my car and keep soup hot for lunch or dinner. I see alot of beverage plug-ins for hot beverages, but not a "food type" thermos.
I got one for my sister years ago at Wal-Mart. She had an outdoor job (here in Northern VA) and loved it. It worked for several years until she moved to Florida :) I'd also try Southern States or Tractor Supply. Good luck!