I'm trying to plan disk space for a virtual environment, and wanting to keep virtual disks as small as possible - mostly as apart from the base OS, the software going onto the VM is less than a few MB, so want to avoid physical disk space going to waste; plus it'll give me an idea of how many VMs I could physically fit in {x}GB of physical drive.

For Server 2003, I've had installs on 2GB and 5GB sized virtual disks. However for Server 2008, Microsoft recommends a minimum of 10GB (I assume this is both for x32 and x64). For the record, I will be installing the x32 version.

Now I know I could just go ahead and try a small install, but wanted to solicit any practical knowledge as well :-) What's the smallest install of Server 2008 possible? (excluding server core installations).