Which Version Control Systems support LDAP/AD users and groups
Solution 1:
VisualSVN Server allows you to manage svn repository permissions using AD users and groups. And the standard edition is free and meets most organization's needs.
Solution 2:
Not to be flippant, but really, just about all of them do. Since PAM on Linux supports LDAP, standard unix accounts (and therefore, standard files) support LDAP, almost all Linux-compatible version control systems should work fine. Likewise, Windows supports LDAP through Active Directory (AD is basically LDAP with kerberos and some deployment tools, as I understand it), and so any version control that works with standard windows accounts should support it too. I'm pretty sure this all applies to OS X as well.