Most of the chain is automated, except for keeping track of new releases and putting the downloaded fansubs into the right (series-)directory. And the first one is about to become automated as well.
Baka-Updates, the aggregation site that I keep tabs on, offers an RSS feed. And the Universal Feed Parser for Python can parse RSS... All I needed to code was a way to store which series by which subbing group I want, and a script that parses the RSS, identifies new releases that I want, and download the torrent files to the directory where Deluge will pick 'em up to download.
In two evenings of mucking around, I have something basic that works. Now I need it to send reports through email if it downloads something, and an email-reading interface so that I can add or remove torrents by sending a mail to a certain address. This will significantly decrease the time I need to spend on refreshing the releases page, and will ensure I don't miss a single release anymore!