I just came across a product call coLinux.
It describes itself as: "Virtualization with VmWare, Xen, and Kernel-based Virtual Machine (KVM) are all the rage these days. But did you know that you can run Linux® cooperatively with Microsoft® Windows®?". I guess the main difference is that it runs a privileged process on Windows, so that if it crashes it will also take the Windows down. In other world it's not *really* a virtual machine! Sounds kinda scary, but it maybe cool for my development box, if it turns out that it takes up fewer resources to run.