I'd LOVE to sleep over at Hogwarts! But, it's been brought up before, and everyone agreed that going from Hogwarts in one place, to Hogwarts in another place--all within the same property--would be pretty ridiculous.
I had a wacky idea once, about an on-site resort all about Universal Studios and IoA. For example it could have two wings, representing the two parks, and each floor on the wings could be themed to the different areas of the park. For example, Wing 1 (Studios) could have floors dedicated to Shrek, Despicable Me, Mummy, Simpsons, MiB, etc... Wing 2 (IoA) could have floors dedicated to Seuss, Potter, Popeye, Marvel, etc...
There would be issues with this type of hotel, though... I don't know that you could make it to look like you're within those worlds in each 'floor.' It might need to have a similar theme all around, like a modern style, and then accents of each of the parks within each section. Otherwise it could look tacky. Also, some 'floors' (Potter!) would be very popular and others not as much