Hello Joe Buckle,
Embedding Silverlight UI elements by using RadRichTextBox's InlineUIContainer may be used to achieve Word-like template editing expericence, but I stress here, not designed for this. Until official support for this is here, custom implementations are possible, but most likely, they will require significant work on your part and may not provide optimal user experience (due to the extent of the API), unlike officially supported features, which are well designed with the user in mind.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!