I've released version 1.02 of my “file-based posts” plugin for WordPress. It allows you to compose/edit posts with your favorite editor instead of the tiny textarea box in a browser. New with this new version is support for nested file includes.
I use the new include feature in this very post to include the ads you see to the right (unless this is not the first post to appear on the page; if ads were already included in a post that appears higher up on the page, the “include only once” feature stops a second ad box from appearing, and hence there may well be no ads to the right.)
See the plugin's home page for details and to download.