I think any reasonably built and stocked fallout shelter would suffice. You could hole up in one of those for a year and just wait it out. And if the zombies manage to get the door open, well, just open up the can o' whupass until they back off and you can get the door closed and braced again.
First order of business, though, is finding the paranoiac who already built the fallout shelter and becoming good friends with him.
