I used to have a post revision plugin for Octopress and I love it. Here is my effort to achieve the same effect in Pelican.

Writing blogs is not a one-time thing. Maybe sometime after you posted a blog, you find a typo, or you get some feedback from your readers and want to further elaborate on some paragraph in your blog, and so on. So keep a revision history for each post is a good idea, not only for you, but also for your readers, to let them know that you're keep polishing your blogs.