Sure, there's options but it takes effort and weighs a lot. For instance, I BBQ a lot (I did at least), look up the Minion Method. Basically, you divide charcoal so that it burns in one direction and mostly from the top down. Controlling the airflow can get you burns for very long times. For instance, in one of my drum smokers, I can get a burn for 18-20+ hours but that's with 20lbs of charcoal. But, that's with a big drum to heat and cooking at 250* or more. Anyway, controlled burn of charcoal briquets would work but it would be a pain.
I guess the question more goes to your end goal. Are you trying to make due with a sleep system that isn't warm enough? To me, once I'm "tucked in" my sleep system should keep me warm enough through the night that having a stove going would actually make me hot. Don't get me wrong, I love using stoves but my sleep system is what I rely on to stay warm through the night. The stove is there for heat before climbing into bed, cooking, drying clothes, etc.