Tobias Luekte has set up a Trac site for his Typo weblog engine. Typo has a slew of neat features including:

• XML-RPC backend implementing the metaweblog api. MarsEdit and other desktop clients work great.
• Comments
• Textile by way of RedCloth
• fulltext search
• RSS2 and Atom export
• CommentRSS export
• Some use of caching and sweepers

So whether you’d like to run it or not, you’ll probably do well by having a look at the source.