Server 2012 has a great feature - Deduplication. It can be very effective to optimize storage and reduce the amount of disk space consumed—50% to 90% when applied to the right data. Cause Windows 8 has a Hyper-V 3 too, deduplication will be very usefull for VM vhd storage volume. This is my VM folder example:
And this example taken from Windows 8 =) So, it's possible to install deduplication service to Windows 8 with one caveat - it'll have no GUI. Only possible way to manage it - is Powershell.