I suggested something like this many years ago. It sounds like an ok idea, but would have to invest a lot of time into programming something like that, just for a section that's not made to be serious.
Not to mention would open the door to doing the same for Blogs, Asks, Intros, ect. Which would just make you wonder why they don't count towards regular posts? Which to answer that question, is because it's to encourage users to be active in the main site and not in the side sections of the site.
Not to mention adding a feature like that would encourage more shitposting.