So going off the end of the world theme and assuming there are only 7 houses here are some ideas I've had
Zombies-Walking Dead has this covered.As I said I can see both a house and scarezone out of this.I feel uni will use walking dead in a lot of the promotion of the event.I wouldn't be suprised honestly if this year is like HHN19 in that the Usher had a great backstory but wasn't used in the promotion to the masses and instead the commercials/ads played up the involvement of Saw/Wolfman/Chucky.
100 years of Horror-Again I can see both a scarezone and house out of this. The house would have rooms centered around the universal monsters,psycho,etc. The scarezone can have a few familar faces from different films.For example while I can't see a house being made, I wouldn't be surprised if the queen from Snow White made an appearance in a scarezone themed like this.It would definitely fit.
Judgement day-A house based on the biblical end would be pretty cool.Imagine Uni reimagining the four horsemen or entering a room where Angels and demons are battling it out?That would really be awesome.I think an idea like this would really suite a soundstage.
Mayan temple-A storyline background that we are part of an investagative team exploring a Mayan ruin to find clues about 2012 would be cool. A room centered around a virgin sacriface or a mayan ripping someone's heart ala caretaker would provide great chills.
Alien invasion-Aliens have invaded Earth and we are hopelessly outgunned.Now we must run for our lives before they turn us into one of their horrible experiments!
Lovecraft/Cthulhu-Monsters beyond our comprehension have risen on Earth.This could an event stealer.Again a SS would really do it justice.
Icon house-Whoever the Icon might be, I think we should go back to giving them a house. If it were Death, a house with each room representing different ways to die would be stellar
Nuclear aftermath-This would make a great Scarezone and they could recycle props and make up from previous years
Mad Max/Road Warriors-A scarezone that would be a post apocolyptic city would be fun.