I am fortunate enough to own a keyring - it was given to our class as a "gizzit" (for the Brit students) or "freebie" (for the Canadians) when I was on a course run by the RAF back in my military days. It's one of those leather ones with a metal attachment bearing the advertising logo (it was from a visit to British Aerospace and has a picture of a Harrier II on it, if you must know). The metal logo, which is square and probably made of steel, turned out to be excellent for striking sparks from a FeCe rod. Keep an eye out at the flea markets and junk stores and you may find one that works. (I have a more expensive keyring, similar in design, with a "Flower of Scotland" logo, which is quite useless for this purpose, as the metal logo is circular and has rounded edges (and is probably not steel).)

I have also found that those triangular binder clips work great; I carry a FeCe rod from Hood's Woods in a plastic ziplock bag, with a small binder clip attached to it, in the container with my Primus Omnifuel stove; just in case I be stupid enough to go camping and forget to bring my usual firestarting equipment, I know I will always be able to light my stove.

I suppose you can always argue these are quite small and finicky if you're trying to start a fire at -40 with frozen fingers; otoh, I've never heard of the TSA confiscating a binder clip, despite the obvious damage you could do with one <img src="/images/graemlins/crazy.gif" alt="" />