Kris Straub talks about modifying WordPress to better accomodate using it for webcomics+news. Tyler Martin's ComicPress theme for WordPress was the first such succesful effort, but it has a few limitations: it only supports one file format and there has to be a 1:1 relationship between posts and comics. (If you can live with those limitations, however ComicPress works well).

Straub (from what I understand) wrote the update system for Blank Label Comics, so I've no doubt he should be able to come up with something useful here as well. Maybe if we all ask nicely he'll release his new creation to the public...