Blogging Roller

The Roller backend is all interfaces. We have one implementation of the backend that uses Castor-JDO for persistence and we have another that uses Hibernate. It would be fun to try to create an implementation that uses the Blojsom file-store. The WeblogManager interface could probably be implemented using Blojsom, but what about the BookmarkManager and the NewfeedManager? Maybe those could be implemented by using OPML files.