I've just published a simple little PyBlosxom plugin called draftsdir. It solves a personal itch for me: I'd like to review draft blog entries on the site before they go live. The plugin lets you define a directory for draft entries which aren't shown unless you add a query arg to the URL (the default arg name is "drafts" but there's an option to change it). When you're happy with an entry you move it from the drafts directory to where your other published entries are. Simple.
For more details see the Code section of this site, the bzr repo or download it directly. There install and configuration instructions at the top of the file.