That would be awesome, but can you imagine how large and expensive they could be? My 9 year-old son is a LEGO JUNKIE!!! He LOVES LEGOS and would probably jump at the chance to build the Haunted Mansion (outside only) if he could, but it would probably be quite expensive (we've found that most pieces average about $0.10-$0.15 each) because of the detail that would be involved. I guess it wouldn't be too difficult to create smaller sets with some of the Disney characters. Maybe you could write a letter to the Lego company or Disney themselves to create special sets to sell at their locations?
I am picturing a large replica of Cindy's Castle in the middle of my living room, made out of LEGOS...