I just imaged 30+ Computers using Proxmox 3.1 with OmniOS, (FOG and pfSense) KVM.
The images took about 9 minutes for 60GB. All the images were done at the same time. I don't think you can say Proxmox is not production ready.
May not be a big deal, but for 6 - 3tb Hitachi Drives, working in such...