Just a note: this article is entitled "Install the Hyper-V Role on a Server Core Installation of Windows Server 2008", yet it does not contain the actual part where you, you know, add the role ... "ocsetup Microsoft-Hyper-V"
Adam, thanks for the feedback. To clarify, as mentioned in the opening paragraphs, you can find all the infor on ocsetup options here:
"You can find more information and a sample Unattend.xml file in the Server Core Installation Option of Windows Server 2008 Step-By-Step Guide (http://go.microsoft.com/fwlink/?LinkID=100959). This guide is also available as a download (http://go.microsoft.com/fwlink/?LinkID=68556)."