I did just run the networking services on the controller so I just have controller/service node and as many compute nodes as I like - no network node.

I now also have the controller/service node in HA active/active - using pacemaker for the couple of services that need to be run in active/passive.

I also use removed the need for cinder block by using our EMC SAN - using the cinder-emc-direct driver on the service node and registering all nodes with the SAN over iSCSI. And I also removed the need for Object(Swift) by using the SAN again to mount NFS to the Service nodes (glance store).

Just about ready to role into production - just LDAP left to configure! :-)