Many thought that Configuration-Only Export of VM is not anymore in new Hyper-V Server 2008 R2. In fact it has gone from UI but it can be done through PowerShell script. The ability to do a configuration-only export of a VM is available via SCVMM R2, However, if you are not using SCVMM, you can script against that API. Here are a couple of sample scripts (VBScript) for doing the configuration-only export of a VM and for importing that VM.
You can find the script at the below Technet page:
virtualization/archive/2009/ 05/29/hyper-v-r2-import- export-part-6-so-what- happened-to-configuration- only-export.aspx