Is there anywhere on the WordPress site that links to users’ blogs that are using a particular theme? I’m sure I browsed several before selecting my current theme, but I’m darned if I can find any way now of visiting WordPress.com sites on a specific theme.
You can view the 170 themes in the Themes Showcase and there you will find some of those who use it in the right hand sidebar. Every theme also has a libe demo site as well.
You can also use Google search to locate other users of any WordPress.com theme. Here’s an example. I use Reddle on my blog. The footer credit links are: Blog at WordPress.com. | Theme: Reddle by Automattic. If I use that searach string in in Google Search the results will be others using the same theme.