I second "trailer park." The only downsides I see are that they might be very small inside, and people might tend to go full-theme and junk up the yards (which can be fun, just maybe not appealing to some.) I've done a few on mainland and always had a good time with it.
I also love futuristic places, and was excited about Horizons initially. That could have been a neat Linden Home theme.
Cliff houses and mountain lodges would be great, also. A lake and/or caves nearby, hiking trails, overlook parks...