Ah - that is a bit different that what you described.
The best way to do that is to have a local daemon running to receive a message
after the remote has booted. Then you can have a local application connect
to the local daemon so the daemon can inform the application which system
has booted (and perhaps some status..) then the application can either do
its' own video, or use VLC to play the video appropriate to the message.
You might even be able to use the dbus network connections to simplify this as
that might handle the necessary authentication and identification for you. The
daemon side would then already exist.
The problem with having the remote server login and display something is that
the remote authentication to the local system does not include X display
authentication. Which user on the local system has the display, what if it
isn't logged in...or otherwise occupied.
Now if all you want is to monitor and know when the remote system is available
look at nagios (http://www.nagios.org/
) - it has several ways to tell when a remote
system is up/down, all accessible via a browser.