In an interview with Metro Magazine, Sly said he's already begun work on "Rambo 5".

"I would like to take Rambo to another genre,experiment a little with the character.It would definitely not be another war movie, cuz I can't go any further with that than what I've already done. What it's going to be like I'm not going to reveal at this point. But I'm already halfway though writing the manuscript".

http://www.metro.se/se/article/2008/03/06/20/3035-45/index.xml

They were actually able to understand what he said? Wow.

I have a feeling if Estelle Getty was in good heath, about now we would be hearing talks of Stop Or My Mom Will Shoot II