Here's list of variables used by MED-V 1.0 SP1 organized by use context. During VM Setup process, there's an optional action to rename computer. When configuring this process in VM Setup tab, you'll see an option for "VM Computer Name Pattern" near bottom of the page.
For e.g., a common task needed by many MED-V v1 admin's a way to automate adding a regular MED-V user into local admin's group. This's an example where use of this command line option with associated variables comes in very handy. In this particular case, we use following command/argument combination:
Arguments: "localgroup /add administrators %MEDVDomain%\%MEDVUser%"
There's also a %MEDVHOSTNAME% variable that's set in operating system of guest VM. It's a system variable that defaults to host name of the host computer.