Hi bhar0761, for as much as I have read you can't get Samba to act as a domains controller because of file replication issues, this is what I could understand from Samba doc's at their site.
For the active directory replication I have many posts and logs mentioning that it is very hard to do if even possible. Never the less here are two links I managed to get the first is for a doc on active directory, an exe to retrieve the AD from a domain controller and also an AD Schema on XML th second is W2k_iop_kit.exe which appears to be a inetorgperson implementation for Windowz.
Hope this helps you in any way.
At my work I have one FC3 fileserver with rpc connection to the domain and a FC4 with kerberos auth also fileserver both stable the last one I tried to sync something from th DC's but with no luke, i'm no expert in ldap and I had no time to continue researching.
Please post any develop as I'm also very interested in this matter.