I put extra lighter fluid into a washed out bottle of tobasco sauce (the tiny bottle you find in MRE's)

Course, it's glass but fairly thick for it's volume so I don't think it should break accidently dropping it unless you hit something like concrete....

I'm not sure if the lighter fluid will eat the plastic cap off, but it's been about a month and so far it's still hasn't leaked at all.

Still, there's nothing like backup, so you might want to carry a mini bic with you as well. Some people like the "permanent match" type devices, which seem to hold the fluid without evaporating longer.