Mortal Kombain is basically a null-mod - just a set of rules to play in vanilla FS2013. Basically, it's like sumo, but with front loaders. You get on the bridge and try to push the other guy off it.
When I was exploring the Hagenstedt map, only 2 places really caught my attention as a potential Mortal Kombain arena: the bridge at the top of the map, and the raised platform on the train station near fields 10, 11 and 12. Since then, the bridge was tried multiple times, but for some reason or another, the platform was left unexplored. Yes, it doesn't provide a satisfying "automatic dismount" option when you throw your opponent out of the ring, but it has nice asymmetric disposal options: you can simply throw your opponent over one edge, or dump him into a freight car. (No dumping occurs in this video, but I'll upload more later to this playlist).
You can also notice that the Agroliner-Lizard match-up looks unfair, but that's something only further playtesting can affirm.
You can join Mortal Kombain Steam community here.