That may not be necessary anymore - theymos suggested I should use the sitemap.xml page. It's a little convoluted, but I managed to hack together a script that will check for deleted/updated posts.
Does this allow you to track all edited posts? More specifically: can you track all posts in which a (spam) URL was added later? I've seen many spambots do this to create a backlink without quickly getting caught.
Yes, absolutely. In fact, the reason why I haven't released any updates for the search engine is because I'm waiting for my scraper to catch up on the back-log of edited posts. Admittedly, it could take several months before it's finished. I just hope a firmware update doesn't force me to reboot before then.