Been around since Windows 2000 (resource kit)... and I've not yet seen it.. anyway, one of the guys I work with found it, so I'm blogging it so I don't forget it.
:)
GETMAC [/S system [/U username [/P [password]]]] [/FO format] [/NH] [/V]
Description:
This command line tool enables an administrator to display the MAC
address for one or more network adapters on a system.
Parameter List:
/S system Specifies the remote system to connect to.
/U [domain\]user Specifies the user context under
which the command should execute.
/P [password] Specifies the password for the given
user context. Prompts for input if omitted.
/FO format Specifies the format in which the output
is to be displayed.
Valid values: "TABLE", "LIST", "CSV".
/V Specifies that the detailed information
should be displayed in the output.
/NH Specifies that the "Column Header" should
not be displayed in the output.
Valid only for TABLE and CSV formats.
/? Displays this help/usage.
Examples:
GETMAC /FO csv
GETMAC /S system /NH /V
GETMAC /S system /U user
GETMAC /S system /U domain\user /P password /FO list /V
GETMAC /S system /U domain\user /P password /FO table /NH