I have a default Minigame script that starts as soon as your dedicated server starts. It has a few bugs to work out but it does the job at the moment.
If you have RTB you can modify many of the minigame preferences from the RTB menu.
You can find the dedicated minigame script here:
http://scatteredspace.com/forum/index.php?topic=6.0 (Note: you will need to register to download the .zip attachment)
As for a TDM auto dedicated minigame system, it is very hard to do because of the way Spaceguy has written the Team Deathmatch script. It requires the owner to be identified and the first person in the minigame to be identified as well which makes automatically starting it up a challenge.