Hi there,
I've build the Minimal Server Appliance based on SUSE Linux Enterprise Server 11 SP1 64 bit Just Enough Operating System (JeOS). It has all minimal server package with DRBD+Heartbeat from High Availability Extension (HAE) Addons and all Zimbra requirement package.

The Appliance was successfully tested to running Zimbra Collaboration Suite 7.×.x (last testing with Zimbra 7.1.3) on VMWare ESXi, Proxmox VE, VirtualBox and KVM Virtualization.

Please take a look : Minimal Server Appliance – SUSE Gallery, you may download or clone the appliance project to build your own.