If you'd rather watch a video than read
Spoiler:
So I had a go at making a cage match typish gamemode. I think it turned out pretty well. There are two sides to the map, a cyan side and a magenta side. When you kill a titan on one side a titan with the same type and size will spawn on the other side. The goal is to clear your side of all titans subsequently filling the other side with titans. Its pretty hard to do with equally skilled teams especially with short respawn times so I'd recommend punishing respawn times. I also highly recommend turning on the minimap and pressing 'k' to reset it.
Setup is pretty simple. All you have to do is load up the map and script, turn on teams, set up the titans how you want them the same way you normally would, /restart, and type '/start'.
I've made a k map to go with this but also cowcowtony's version of Feng's forest with a couple of edits to make it closer to the original.
Important Note
There is a bug that causes titans to be invisible to everyone except MC when '/start' is used. The simpliest way I've found to fix this is to go into fullscreen mode and back out. The titans will also get fixed if they sit down or get killed so the problem goes away after some time.
Other Notes
Wave mode works but the titans will track you from any distance. This means that they may track people from the side they are not on and end up grouped at the wall.
If there are an odd number of titans the cyan team will get the extra one.
The two sides are mirrored. So if you kill a titan near the divider it will spawn close to the divider on the other side.
If someone not on a team kills a titan they will be killed.
If someone on a team kills a titan but they are on the wrong side of the map they will get moved back to their side.
Player titans do not work.
Screenshots
Spoiler:
Me vs. Zechten
Spoiler:
Logic
http://pastebin.com/W9Mr5Fme
k map I made to go with the logic.
http://pastebin.com/kVMLW98k
cowcowtony's version of Feng's forest with some small edits to make it closer to Feng's and modifications to work with the logic. (thats a mouthful)
http://pastebin.com/KnE1xbgc