Our partners at Sun and AMD have used VMmark to produce an interesting virtualization scaling study of the Sun Fire X4600 Server. You can find a short version of the results at http://www.sun.com/servers/x64/x4600/VMScaling-Final3.pdf. A longer paper can be found at http://www.sun.com/servers/x64/x4600/VMScalability-wp.pdf.
One of the primary goals of VMmark is to provide appropriate data to customers as they design and build data centers to support virtualization. Studies like this one can help customers make informed decisions. Stay tuned as we continue working with all of our partners to make more information like this available.