Just in case you missed it, over on SystemCenterForum.org they have begun a neat series of posts on how, when and why to virtualize System Center Operations Manager 2007. I copied the intro below but you should definitely check out the original post here.
Questions about when and how to virtualize server roles in Operations Manager 2007 is something that comes up more-and-more all the time. Certainly there is some guidance for this already in the product documentation (like the OpsMgr IPD Solution Accelerator), and on the product team blog and other blogs. But nowhere do you see thorough best practices guidance at the nuts-and-bolts level when virtualizing Operations Manager 2007 on Hyper-V....
J.C. Hornbeck | Manageability Knowledge Engineer