The Sitefinity 3.1 release is planned for the second half of September. It will come with a forums module, which is still in development and not fully functional, so we cannot show a beta. Regarding a repository for third-party modules, we definitely think that it is a good idea, and are already planning something like this. It will not be for modules only but for any code developed by third parties. We still cannot say when we are going to do it, though.
the Telerik team