Couple of years ago the Evil Bitch Queen From Hades inexplicably bought me a really useful piece of kit - a Kelly Kettle.
Kelly Kettle® - Original & Best | Camping equipment | Camping gear | Survival kit - Home
Its a cross between a water heater and a cooker. Looks like a cut-down fire extinguisher and is a bit too big to manpack. The idea is that you can use any available source of flame - twigs, dung, hexy, and the larger size will bring 1.6 litres of water to a boil in 3-5 minutes. This can be done with two hexy blocks, so its very fuel efficient.
There is a gizmo that lets you put a pot / frying pan on top so you can cook at the same time as boil water.I've used it on ex a couple of times and it does work. I'd think i would be a very welcome addition to a remote FOB where cooking fuel is scarce, or packed in a vehicle read for use by the brew bitch.
Boils water quickly, very fuel efficient, good piece of kit.