Semiologic theme is the closest I have seen to a WordPress installation becoming a CMS. Semiologic is not for the beginning WordPress user and I’m not sure it could be adapted to an existing blog. But if you are starting a project that entails more then just a blog, and want to use WordPress I think you will be impressed with Semiologic.
Here are some of the features.
- The front page has a non-standard behavior; it will display the page with a slug of “home”, and if none is available it will display the last posts in the category with a slug of “blog”
- The sidebar displays the latest in categories with a slug of “news” and “blog” separately when these are available, plus the latest comments grouped by posts
- Posts in the category with slug “highlights” are highlighted in red when they are displayed in lists
- The header and footer navigation menus are automatically updated to reflect your having pages with a slug of “solutions”, “products”, “services”, “resources”, “downloads”, “legal”, “about” and “contact”
- Categories and search results display an unlimited number of post/page titles
- Search results are sort by name rather than by date
- You can easily customize all this by editing a few arrays in the plugin code; their names are hopefully self-documenting
My suggestion would be to browse the Semiologic website before diving into using this theme.