What you want is a totally normal usage of ldap, nothing "interesting" at all. Just configure ldap in pam to point to those servers and also nss_ldap for obtaining the home directories and the likes. Enable pam_mkhomedir in pam to create home directories as required. Not that it doesn't make sense to store the home dirs in the "ldap server", consider the ldap server to be a server process and data files - NOT the machine itself.
If you have no ldap server at all yet, then openldap will do this job just fine with a fairly default installation. Just remember to do ONE THING at a time, and be sure of that stage before moving on to the next. For example, make sure "getent passwd" works on a client before expecting a full on login to work.