this is a really neat idea, and you gave myself another idea you can bring from the firearms world.
Rust bluing.
its an amazingly simple [but lengthy] process of turning rust into magnetite. its a durable finish that can be coated in boiled linseed oil to keep from further rusting.
i have rust blued a few parts, and the results are extremely beautiful. i havent taken any pictures, but heres a good example of before, during and after.
NOTHING in the world goes better with wood then rust blued steel. so if your interested in doing a few small parts this way, just shoot me a PM. the cost for materials is less that $20,