Though this is a late response I wanted to point out that we just released an Active Directory Reporting and Auditing tool. It can be found at http://maxpowersoft.com/products.php?i=1.

Unlike some of the software packages mentioned here actually get the "real true last logon". We also allow for customizable reports. Our system is robust to the degree that we take into account that you cannot audit Windows Active Directory via LDAP queries alone. You actually have to have programmatic logic that that takes into account your domain policies. We do this and we are eager to help you get the results you need.

Kind Regards,
Chris Danielson