I think Cliffside Neighborhood will be great. Different from the current themes that seem to embrace real life traditional building. These homes would offer a step toward making dreams real in SL. Here are some examples: https://gyazo.com/e016b07a76da1499d15f6c0dba5fb737

Instead of bicycles and boats you could give some kind of flying pod or da Vinci wings. I bet a lot of the non-human avatars (vampires, lycans, monsters, flying avatars and such) would flock to these cliffside homes.