Windows 8 lets me create user accounts simply by the email address of a Microsoft account (aka Windows Live account). Is there someway to activate such a facility in the Windows Server 2012 SKU?
There is not a way to add Windows Live accounts to Server 2012.
You can add some of the client features via the Desktop Experience sub-feature under User Interfaces and Infrastructure, but Windows Live authentication is not part of that feature set.
Are you looking at running the server OS as a client machine?
UPDATE: If you are looking to have some sort of shared management structure, you may want to look at creating a domain and associating the domain accounts used on your Windows 8 boxes with a Live ID (to get all the settings synchronization that provides). Then you can assign perms via the domain.