Most of the projects that we handle does not use a pure Microsoft stack or may require a third party software to be pre-installed. Managed VMs will give the clients to pick, choose and install their software combinations that they are most comfortable with while they rely on Microsoft for hosting.
P Velachoutakos commented
Also to add the ability to use preconfigure iso images like Amazon does
I truly hope for managed VMs sooner rather than later, it will open up new possibilities with Windows Azure, which today is only possible with third party providers. +3!
Check out http://microsoftpdc.com/Sessions/SVC13 and go to 37:55. You will see a slide which indicates this is planned. Is this what you are looking for? Last week I also blogged about it here very briefly, http://blogs.msdn.com/wickstrand/archive/2009/11/23/pdc-09-your-great-windows-azure-ideas.aspx
Thanks - Mike
very good idea!
choice & freedom!