I bought a wood fire piston off ebay to try out with my 6 year old. Last summer he built a fire with a sweedish flint by himself. It only took him 7 hours and he wore out the flint that was advertised as good for 10000 strikes.
So now we are playing with the fire piston. It works quite well and is a lot of fun. You have to push it in and pull it out quickly to get it to work. It makes a coal about twice the size of a match head.
These would be simple to make. I might give it a try.