I wonder if LaBeouf is referring to the Bermuda Triangle plot that was being kicked around a couple months ago as the possible subject of a fifth film (which producer Frank Marshall purported to refute). That sounds like fun to me -- but then, I'm the guy who was pilloried for admitting an affection for Crystal Skull in my earlier post. I expect most of you won't think much of the idea.
But despite (seemingly) widespread fan disgust with the attempt to revitalize the franchise, Crystal Skull made nearly $800 million worldwide. A fifth film would also assuredly make a huge profit, which Spielberg, Lucas, LaBeouf, etc., surely know. Thus, the inevitability. And look: is any Spielberg movie ever really something to dread?
In any event, Spielberg will finish filming War Horse before having a chance to turn to another Indy. So smoke if you got 'em. We've got at least two more years to wring our hands.