Integrate Virtualbox/Qemu Guest booting as a desktop environment listing (request)

I had seen this new way to install Chromium OS and "boot" it using LightDM's session select menu, and it made me think of an idea:

What if you were able to boot virtual machines in the same manner? It would simplify the Ubuntu user's life GREATLY if they had easy access to a Windows VM that can synchronize their files to and fro (Guest additions) and not require a reboot to use it. Modern computers have more than enough power to do something like this, and it should be even easier if the system is using a dedicated virtual machine environment rather than a full blown desktop.

This can transform LightDM from being just another login screen to a full-blown glorified host for all of your operating systems and remote logins.

I think this would make using Ubuntu a LOT less of a hassle for the new user who came from Windows :)