Following up on Shia LaBeouf's tease from earlier this week, producer Frank Marshall has confirmed to Empire that INDY 5 is in development. According to Marshall, "We had a great time making the last one and, as Harrison said, we need to make this one soon. We're not getting any younger."
So, yes, Harrison, Steven and George are all on board for this fifth movie provided they can settle on a script. Marshall says he hasn't heard the "cracked" idea Shia recently spoke of, but he did drop this nugget on Twitter a little bit ago: "The story for Indy5 is progressing. It is still in the research phase."
Though the excuse for making this fifth film is that they all had a blast making the fourth, I hope the true motivating factor is "We're sorry, and we can do better."