In Thailand I've often seen outdoor cookpots like the one below. Googling the term Thai charcoal burner will return the bottom part of the device pictured. It's filled it with charcoal and acts like a stove.
The middle and top parts are used when cooking sticky rice. The middle part is a thin metal pot that holds at least a few liters of water. The top part is a bamboo basket which holds the rice. When the water in the pot starts to boil, the rice is steamed. While steaming they typically cover the rice with a lid. Sticky rice is normally pre-soaked but I'm not sure if that's necessary for other types of rice.
Wikipedia provides this picture by Feral Arts under CC-BY 2.0:
I'm not sure if this works with regular rice, but I don't see why it wouldn't. From what I've seen, Thais mostly use electric rice cookers when cooking jasmine rice.
Of course this setup can be adapted to your situation. Bamboo steamer baskets and corresponding pots are probably available at local Asian stores and the steaming can be achieved by any kind of heat source.
The only thing to be mindful of is that the bottom of the bamboo basket does not touch the boiling water because you want it to steam.