Presently, we do not have plans to build stand-alone RadForum or RadBlog controls . One of the main reasons is that a forum or blog control encompasses quite a lot of functionality, and would be more conceivable if its implementation includes more than one control.
Nevertheless, you may be interested to look into the following demo:
or consider utilizing our Sitefinity CMS modules (as suggested by Ivo before), demonstrated here:
the Telerik team