They don’t actually use the Topic List Previews plugin at all, the topics in the carousel on the homepage are displayed using a custom theme component. The topics are set with tags and pulled in as jcarousel slides using AJAX. The images are set using a field in the theme settings.
The rest of the look of their site is custom CSS in a theme.
Anyway, that being said Topic List Previews is probably the easiest way to get something similar at the moment. We don’t have a “featured topics” theme component available yet (but it seems like a popular request, so maybe that will change in the future).