I treated myself and purchased an Exotac XL matchcase http://www.exotac.com/matchcap-xl/. It's pricey, but really well made and designed. (I know, spend 32 bucks to hold 2 bucks worth of matches?) It shields an interior striking surface from moisture - a unique feature AFAIK. I haven't had to use it yet for real, but I am pleased with it.

Exotac products seem to be well designed, and are definitely expensive, but in the right situations, look like the tool for the job. I have no affiliations with the company, other than being a satisfied customer...