Regarding the Pellet Stove mentioned in a recent post, here is what the manufacturer has to say about using them in campers:
And now, the newly certified models: The Teton
and The Sierra
, are available to heat off-the-grid cabins, line shacks, and detached shop structures or out-buildings. The powerless pellet stove is also the perfect solution for an ice fishing house. No Clarry® Stove is to be used in homes, manufactured homes, mobile homes, motor homes or camping trailers.
I think it's probably best to invest in a great sleeping bag for the really cold nights.