I will put .map files with 12 player options tomorrow. Really busy weekend, huh. But I guess MP game with 24-player version free-for-all elimination deathmatch [so 12 players left after early bloodshed] could be really interesting. But it's not good time of the year to start new games, so maybe in 1-2 months
P.S. No, do no try to open map file in map editor and modify terrain/neighbours etc there and save it as same file! It will annihilate all your other things in the .map file, as it overwrites it with just what you have in map editor
So new name and copy special content there [but be prepared to recheck all neighbours, as map editor loves to change them].