Is it possible to start an additional X server after the system boots in 12.04?

I'd like to have 2 VT's running, one on VT7 with the standard lightdm + unity interface and another on VT8 running a custom script which will launch a virtual machine in full screen.

At the moment I've tried writing an init.d script with no luck and I can't find any details on a configuration file which will allow me to start 2 servers.

I suppose my ideal answer would be one which points me to a config file I can edit to start up an additional server.

Edit - I forgot to mention in the text that I already know how to start another X session: I'd like this to start automatically at boot.

Yes, it is possible. I do it for games.

xinit session -- :1 -xf86config config.conf

Where session should be replaced by the session you'd like to start in the new Xorg display, and config.conf is the configuration file.

For starting it automatically, take a look at this answer.

I am not sure about a config file that you can edit, but I do know how to start another X server. Assuming n is the TTY number that you want to start the X server on, the command is

startx -display :2 -- :2 vtn &

You will then get a small white terminal window on that TTY that you can move your mouse in. From there, you need to run the command to start a window manager (e.g. gnome-session) from that TTY.