Can I configure OWA (2010) to tell a user when their account is locked out?

Solution 1:

No, possibly for security reasons. Users should not know that fact. Well, THE user may want to know, but the HACKER that tries to log in as the user should KNOW know that his password attempt was not rejected for a wrong password but because he got locked out.

Basic security 101 is to give the hacker as little information as possible.