Hey just a thought, but an old bike fork would make a pretty good zombie killing weapon. I would go for something with a very long steerer tube. You could have an uncut one as part of the bike supplies/tool kit and if the one on the bike gets tweaked too bad, swap them out and have the old one become the weapon.

The actual point of the post is, I was thinking of how many things could be put into an actual emergency kit that would serve 2-3-4 purposes. Trying to see how much usefulness can be packed into the fewest items. That is what I like about 'commuter' bikes -- they have a lot of usefulness in a single package.