I have developed a server application which is hosted by an IIS 7.5 running on Windows. Aside from a web frontend the application also provides a SOAP and a REST API. Clients will only interact with these APIs and the web frontend.

I am now looking for a Windows distribution which allows me to distribute the system in form of a virtual machine. I.e. I would like to set up a virtual machine image which has Windows as well as some open-source programs and my own binaries pre-installed and ship this whole VM to my customers. This would minimize the efforts required for setting up the system at a customer site.

Originally I wanted to use Windows Embedded Standard 7 as OS, but it appears to be prohibited to ship a WES7 as virtual machine, because Windows Embedded OS must always be bound to a physical device.

I would like to know which x64 Windows edition would be best for my needs:

* Hard requirement: Can be pre-installed on a virtual machine and shipped as such
* Hard requirement: Volume licensing available
* Soft requirement: Small memory footprint
* Soft requirement: Cheapest Windows that allows this.
* Soft requirement: Preferrably no manual activation required (like Windows Embedded, where you only need to attach the license sticker to the device)

Context: My system is a monitoring/reporting system for industrial machines. It retrieves and aggregates data from industrial machines and makes it accessible through web frontends. The data is usually considered confidential, so users would not be too happy if we uploaded that data to some server on the internet.

I really need a Windows OS, because some of the components used are only available for Windows. I cannot use Linux.