A lot of interesting speculation, I like it!
The idea of popular literary works as themes for houses is an interesting one. Now, these opinions are coming from someone that has no connection to Universal pretty much, but it seems to me like it wouldn't exactly intrigue a lot of customers. However, the idea of having one single house with several rooms based on different works, I would love to see (I.e All Night DrIvE In or The Usher's house in '09 - blanking on a name - with literature and not movies).
I would love to see Eddie make an appearance! I can't explain how frustrating it was to walk through and entire park of "I.C.U." and never actually see Eddie. (though finally seeing him in this past years scare zone was cool.) Eddie is the type of character thy would appeal to HHN newbies and hardcore fans.
As for anything from Stephen King, after watching an interview with him about a month ago, I'm not sure he would give the rights to do something like a haunted house. He's very insistent about being extremely involved in any kind of recreation of his novels, and I doubt he would entertain the idea. But im not gonna lie, it would be an instant classic.
But there's my two cents.