Yes, there are a few sites out there like
http://www.warp2search.net,
http://www.idlepaws.com, or
http://www.wcm.at but none is running it with UBB.threads integration yet.
I guess it is only a matter of time. I plan to upgrade compatdb.org and my other sites later this month to Contentteller, so there will be at least one site that is running Contentteller with UBB.threads integration