I really hope it's VV4, and if not, it comes out soon. Very soon.
According to the evidence available, it's probably something fresh, but there's always a chance.
Loki, there are always sticky problems when using someone else's idea - if they were going to use your idea, I think you'd have been asked to sign a form or two. EDIT: Also, a lot of work goes into preparing to program a game; we only see the progress done in the programming on the chart, but a lot goes into determining what it is they actually want to create. For example, before writing VV3, I'm sure they knew exactly what they wanted every single puzzle to consist of.
Lastly, what else is there? Bugs have been mentioned, using the VV2 assets. Robot factories, perhaps? But that would only be another form of Virtual Villager. Well, we'll see in due time.