I graduated from the Physics and Mathematics Department of the University. I understand the whole complexity of the task. Most people will say that this is impossible.
But as a mathematician, I say that nothing is possible. The main things are: Luck, Time, Resources. And we are sure that the reward is worth it.
Its really impossible if you can do such thing. Why wont bother on searching for investors if you can totally crack some privatekeys and get some funds to make development on what you are proposing on here?
This would really involve lots of work even tracing or recovering a single private key this is why once you lost it then don't bother to recover.