Blosxom now has a rating plugin, which produces numerical, textual, star and graphical representation of ratings mentioned in blog posts (eg book/CD reviews), using a 'meta-rating: n' string to store the actual value.
Maybe this could be extended to add RVW data to the post or the RSS feed. It certainly seems a lot easier to do 'search-and-replace'-style plugins for Blosxom than for Movable Type.