Disclaimer: This is all theoretical discussion and nerdy speculation with some fun pictures along the way.
With Halloween's approach coupled with the growing popularity of The Walking Dead (on AMC), my chapter of the AIAS has taken on a Zombie Safe-House charrette and school-wide competition. Our inspiration for the competition was found here.
Despite the designs I have displayed below, I tend to disagree with a hub where millions of people collect themselves. In a plague situation, as this more than likely would be treated, the bringing together of people would be detrimental (as we have seen in horror stories before). There is always one rule-breaker who hides their contamination, or the contamination of a loved one and brings ruin to those who have found shelter. I feel like "putting all of the eggs in one basket" here is a bad idea. Therefore, the most successful design in my opinion, would have to be one that allows for contact with other humans for socialization, but in a regulated manner, with some severe screening (possibly Haz-Mat style) to ensure that those present were not already infected, and which can be broken down into single-family units for privacy and comfort as well as a type of private security/quarantine.
I like the noble idea of searching for a cure, but to include this in your primary housing facility is also a bad idea. any testing of the undead should also be regulated and kept far away from those living sectors.
Unfortunately, I'm not a fan of turning existing monuments into shelters (i.e. The Statue of Liberty or Eiffel Tower). There are a few entries like these, and do not let me dissuade you if you think they are strong, I just don't think they are a solution most people could consider given the apocalypse, and despite Darwin's survival of the fittest, I feel the resources it would take to reach these places (or ensure food delivery, ecological regrowth, etc) would be so astronomical that it wouldn't be worthwhile.
Islands are an interesting idea, but it would depend on the zombie you are referencing. Unfortunately, there is a type of zombie, I am told, that walks along the bottom of the ocean. it cannot swim and does not need to breathe, thus its ability to sustain itself. But I will set aside any more of this "nerd-ism" in the interest of the designs.
I want to encourage you to vote on your favorite designs (until October 31, 2011) as many entrants have put a great deal of work into their designs.Enjoy!! :)
(These are just a small selection and are shown in no particular order)