Citrix XenDesktop would work (Score 1)

(full disclosure up front, I'm a Citrix employee)

Either Citrix XenDesktop would work for your scenario.

XenDesktop VDI edition would let you maintain a single OS image .VHD file in your datacenter. You could run it on Citrix XenServer (based on Xen.org hypervisor) for free or swap in VMware ESX/ESXi/vSphere or Microsoft Hyper-V, whatever your preference is.

Stepping up to XenDesktop Enterprise or Platinum Editions would allow you to take that single .VHD image, skip the hypervisor and stream it directly down to each different endpoint device. You would just need to prep the image to ensure it has all the neessary drivers.

XenDesktop Express is a free edition of the product that you could also use for up to 10 endpoint devices using the first delviery method. You would need to clone the .VHD image for each system as the provisioning component that allows single image management isn't available in the free edition.

http://www.citrix.com/xendesktop - Product Page
http://www.citrix.com/tryxendesktop - Free trial

Incidentally, I noticed somebody point out Citrix XenApp as a possible solution earlier. That product would be better suited to virtualize the applications not the entire desktop. It is included with both XenDesktop Enterprise and Platinum Editions as well.