Some people think they are here already. Terrence Mckenna proposed that spores are one such possible Von Neumann vessel. Spores are very resilient and could possibly travel the universe. Time is irrelevant to a fungi. I haven't finished reading his thoughts, but I think he's onto something to be honest. You can read more about this in the "Archaic Revival" Really great text for changing your existential perspective. Very intelligent man.