An 8th Harry Potter Book? a real possibility?

I know that shes released the 7th and supposedly last book in the Harry Potter series. However do you think it really will be the last one? She has hinted around the selling and after that she is considering expanding the series. She is talking about an Encyclopedia on it. Also She has sued companys attempting to make parodys of the book saying it prohibits her from making another book. If she does create another book what do you think it will be about? Would it be movie worthy? could she write a book along or after the encyclopedia?