Yes, AD is NOT required. You can create your own tree struture in ePO and utilize sorting and/or tags to arrange systems accordingly. You should be able to register your LDAP server in ePO and that should aid you in deployment of the agents via ePO should you choose to go that route. Also note that whatever name is defined in the systems Workgroup field a corresponding directory will be created in ePO under Lost and Found
Just to add one thing here - I'm afraid you won't be able to register a Novell LDAP server, for example an eDirectory server, with ePO. You'll need to treat the machines as though they were in a workgroup environment and authenticate against them locally when you install the agent.