[Samba] Can Samba + (OpenLDAP & Kerberos) completely replace ActiveDirectory?

[mikel king]

I am sure this pops up on the list ever once in a while. I have inherited a LAN that have a large amount of Mac OS X, FreeBSD, Linux and of course because bean counters have to use financial apps that only run on Windows. My long term goal is to install some sort of central management system and really feel that AD is not in my best interest considering that 90% of the 300+ computers are not Windows based. Unfortunately the 20 or so Windows machines are running mostly Win7 and there are some 2k8r2 servers in the mix somewhere. 

Does anyone know of any good how-to, best practices/guidelines sites or documents?

Thoughts? Suggestions?

Respectfully,
Mikel King