Any ideas reference heaters for slide in truck camper

[Truefire]

Anyone have any ideas for heaters for a slide in truck camper? Looking denatured alcohol heaters to use with ventilation. The heater would be used when power is not an option which could be quite often. I am familiar with Origo type heaters but i was wondering if there are some units out there for hunting type, hike in camping that were smaller in size but just as effective as some of the larger Origo type heaters measuring approximately 11.25" diameter x 12" tall. Just need something much smaller but just as effective,

any thoughts

chris

 

[Borrego60]

Have you looked at heat source heaters?