This would be very simple to implement, just allowing a lit torch to satisfy the fire requirement to light another torch.
I sometimes like to have my characters craft by torchlight during the long winter nights and it's annoying to have to have to constantly build fires to keep my torches lit when realistically I should be able to pass the flame from one torch to another.
Also, perhaps some kind of "sconce" type implement that would allow us to mount the torch on a wall or table so that both hands can be free?
I've read threads before stating that bees were not kept in iron age finland, so no beeswax candles. However, were tallow candles, rushlights (
https://en.wikipedia.org/wiki/Rushlight), or tallow/other oil lamps in use at all? It would be fun to turn some seal or other fat into candles or lamps.