"If you had an exclusive Windows-only shop then possibly Disk2VHD could be useful. This tool can run from a USB stick and will churn through a hard disk on an operational system, producing a VHD disk image out of it.

"VHD is the virtual hard disk file format used by Microsoft's Virtual PC and Hyper-V software. This means a legacy Windows 2000 server, say, could be captured and restored as a virtual machine on a modern Windows Server 2008 system ultimately reducing hardware and power consumption."