There actually has been research on how to split passwords across multiple servers (one example http://www.passwordresearch.com/papers/paper270.html http://www.

There actually has been research on how to split passwords across multiple servers (one example http://www.passwordresearch.com/papers/paper270.html http://www.passwordresearch.com/papers/paper270.html), and RSA is currently marketing a commercial product that does this. While I agree that most people probably aren't concerned enough about password exposure to do this, there are effective solutions to accommodate those that are.