At MMS 2009 a new feature of VMM 2008 R2 was announced called Rapid Provisioning. This feature is not available in VMM 2008 R2 beta, but it will be available in the upcoming release candidate and in the RTM version.
This feature was implemented in response to customers requests. In VMM 2008, the only way to deploy a new virtual machine is to copy the VHD from the library to the host over the network using BITS. Depending on the size of VHD and the available bandwidth, this could take several minutes or even hours. We heard from a lot of customers that they have sophisticated SAN technologies that enables them to clone a LUN which contains the VHD and present it to the host. However, customers still want to leverage VMM’s template capabilities with OS customization and IC installation. So they basically wanted new-VM without the network copy which is exactly what we did with Rapid Provisioning. You can now create a template which includes the OS answer file and which references a “dummy” blank VHD which is not going to used. Then, using Windows PowerShell (There is no GUI support for Rapid Provisioning since we expect customers to use this feature in massive deployments that are automated) you can execute the New-VM cmdlet and specify the local path to the VHD using a new switch –UseLocalVirtualHardDisk.
Read more at http://blogs.technet.com/m2/archive/2009/05/07/rapid-provisioning-in-vmm-2008-r2.aspx