There isn't currently, but I have a wish list item in our project tracker for the blog to make it possible to have some extra content that is shown at the bottom of each post in a feed. It won't be per post though it will be something entered in the settings and it will be the same thing at the bottom of each post in the feed if it is enabled. I've been thinking of this as a way to put an advertisement in the footer of feed items without putting it in the blog post. I don't know if that is really what you are after or if it would meet your need, but mentioning it in case it might.
Best,
Joe