You're talking about "Art of the Scare." It was a Travel Channel documentary they filmed in 2002. It gave you good shots of some of the houses (especially Screamhouse since that was the feature house that year), but there aren't any full walk throughs. Fun fact - I'm in it.
The casts ask about it almost every year, and basically boils down to Universal not wanting local haunts to "recreate" what they do. They're talk about protecting their own intellectual property, but that's what it boils down to. It's also why cast shirts require approval by management to ensure it doesn't feature something "uniquely Universal."