Loved this article, Denise! This is something Hyperic (http://www.hyperic.com) has been talking about for quite some time. In fact just in September, we produced a whitepaper called "Managing the Virtual Divide" with Andi Mann, of Enterprise Management Associates (EMA) and VMware. The paper discusses many of the same complexities around managing virtualized environments in production. The whitepaper can be found at: http://download.hyperic.com/pdf/Hyperic-WP-TheVirtualDivide.pdf

Additionally, for more juicy reading on the subject - we happened to publish a case study today on Mosso, a division of Rackspace. These guys power 30,000 websites and applications using 100% virtualization. The virtualization (VMware) they use does not save them money, since their infrastructure is heavily utilized as it is, but it does provide them tremendous flexibility and service to their customers. However, to manage that "virtual sprawl" their team started to break under the pressure. Since they put in Hyperic, they have continued a whopping 60% growth rate, and managed to keep their team the same size while improving service. I know I work for Hyperic, but this is such a good story as it is really an underserved topic in the industry. Check it out: http://download.hyperic.com/pdf/Hyperic-WP-TheVirtualDivide.pdf