I would love to see Far Far Away at a Universal park. I love the idea of a full parody land poking fun at Magic Kingdom. It would hit a lot of the themes that made Simpson's/Springfield work for me (ignoring all the reasons it didn't).
But this may be my unpopular opinion: I don't want to see any castles at USF. That includes Zelda and LOTR. IOA and Epic, to me, work so much better with those kinds of castle / fantasy lands. I'd much prefer USF get something that relates to a modern town or city (even it's a cartoon town like Springfield).