I wanted to ask if anybody has experience in installing CCM without clustering, that is a single server possibly backed-up by a router is SRTS. I would be interested in doing that with 5.x / 6.x
In traditional SRST mode, the amount of features you can implement are limited. If you want huntgroups, call park, pickup groups, BACD queueing etc, SRST has limited capability to do all these functions. (There are workarounds to create a basic huntgroup using alias commands in traditional SRST). With CME 4.0, Cisco introduced CME with SRST fallback support. THis requires that you buy SRST feature set licenses for the router. Instead of "call-manager-fallback" command, you can use the "telephony-service" command like in CME. You will configure a command called srst auto-provision to automatically allocate ephone-dn's when each phone register with the router. In Callmanager you would create an SRST preference for the phones and tell it to register to the CME router's ip address. Check this link for more details.
After configuring the router as per this link, perform a failover from Callmanager to the CME router and all the phones will register with the CME router. Phones will keep their original DN's that are configured in Callmanager. Once the ephone-dns/ephones get generated in the config, you can set up any CME like feature you want.