There are a lot of zombie defense items at SHOTSHOW 2012. I don't know how I missed it, but Gunblast.com has a pic of the ultimate zombie defense item. Quite frankly Colt has 'brought it.' Although they are not marketing it as an anti-zombie gun, I think it is perfect (think Jonah Hex).
That's right -- a frakkin' gatling gun!! Awesomeness!