So this is probably a good sign that the VMs that we ship are used a lot. It seems if you try to register Office on the demo VMs it might start telling you that it has been activated too many times.
So as a partner you will have access to a NFR copy of Office or if you have an MSDN subscription you can get a product key/Id from there to use.
If you are having trouble finding one then get a 60day Eval key from the Office website
Until you can find one that you have more permanent usage of.
8/25 Just adding and addendum as I got a email from Carl. This link maybe useful for some of you have have the office activation issue and you want to use your MSDN license. http://www.mydigitallife.info/2007/01/12/how-to-reset-or-change-microsoft-office-2007-product-license-key-or-volume-license-key-vlk/
Original post at http://blogs.msdn.com/lcash