How can I force X to start in a computer without a monitor?

I have a computer that has no monitor attached to it.

When I boot the system, X fails to start because there is no monitor detected. If I boot it with a monitor attached and after X has started, when I remove the monitor everything works fine.

Details and Background:

This computer is a kind of hardware consolidation server. It's only purpose is to run two Virtual Box VM's that run Windows XP and some important but seldom used (once or twice a month) programs. For a couple of time it has been lying in a corner with an old monitor attached to it and working great.

But space in the office was getting scarce and I moved the computer to the server room. There is no monitor attached to it there (no space), and sometimes the computer is rebooted. When it boots without monitor X is not started, the vms doesn't start and I get called to solve the problem.

According to this tread a possible solution for 10.04 may be to both

define a standard xorg.conf, and
prevent KMS at boot.

However solution #13 there with resistors plugged to the vga port for fake monitor is really funky.

I think it's because Xorg nowdays are designed to run without a config file, that is: some kind of auto-detection. For sure, it has the "problem" that it cannot detect your monitor if it's not there ... What I would do is to create a config file for Xorg server, so you have "hard coded" config then, no need for auto detection.

Run this command from a text VT as root:

sudo Xorg -configure

It will create a config file for you, if I remember well with name something like xorg.conf.new in your home directory. Move/copy it as /etc/X11/xorg.conf, also you may need to customize it a bit. If X works properly with that configuration (try that with a monitor attached first, of course), you can try it out what happens if you remove the monitor.

Check out IgnoreEDID.