What about a good old fashioned club? Idiot-proof and perfect for a fight or flight reflex. I have one for my home defense. I love my khuks, and I know I could do some real damage with the kobra or rose resting snuggly beside my bed frame. However, there is something scary and powerful about my club. My wife calls it my "zombie-killer".
It started its life as a spare post hole digger handle at the local Lowes. I brought it home, cut it down to 31", sanded the finish off of it for a good wet/dry grip. Then I installed two 2" galv. bolts with lock washers and nuts through the predrilled holes to give the club head a small amount of weight as well as pressure points to focus the force of the blow. For a little extra umph I drilled a 2.5" coated woodscrew through the opposite direction as the bolts, cut the ends off so only 1/4"-1/2" stuck out of each side (to keep from bending) then ground both ends to a point. Finally, i put a woodscrew through the top center, cut it off at 1/4", then ground it to a point. Just to give it a great look of meanness I wrapped the head in several wraps of 1/4" wide thin leather. Then I coated the whole head with a mixture of poly wood finish and jb weld. The wood finish melted the weld and made it drip and flow into every little crack and nook before it hardened. Add a hole at the base for a leather thong, and you're ready to crush some skulls. Extensive tests must still be done, but a coconut (the skull) covered by half of a hollowed melon (the scalp) did not offer any real resistance to a 3/4 speed blow.
Bring on the zombie hordes.
Jake