I was thinking of another idea today that is team based and actually much simpler to implement. Wont require a new mod or map. Can also even take place over different gametypes.
The world itself is handled externally with all information on a webpage. Most of the rules are basically the same but closer to standard TDM or objective matches. It is still just as competitive. Think of a board game like Axis and Allies. Meaning... this is war. A world has eight territories, each controlled by a team. Within each territory there are 10 zones, each with a unique map. There are no common maps between territories. For example, Team X may have Pipeline. Nobody else does. Some zones border the territory of your enemies. Your enemy, when its their turn, may choose to attack you to take that zone and add it to theirs. A team match is fought. The winner either retains controls or takes it away and adds it to theirs.
For team signups anybody can join. But once on a team that's it. The team is fixed and you cannot switch. Unless for some reason a player can no longer compete. If so, someone can join the team (who is not already on another team) and take his or her place. This is actually much easier to implement since there are no new mods or maps required. It is however different in that it is total war not hunting. Note that maps can vary. Some may be primarily CQ and small. Others primarily sniper. Maps can be restricted to a single gametype. Say if zone one in Team X's territory is always S&D. Another interesting idea might be many 'free' zones that nobody controls. Except by zombies. Want the zone? Win the match entirely. Very hard to do.
It would be cool if each team had at least 10 players. 8 teams. Meaning 80. But that might be unrealistic. I dont know how many people play here, either as regulars or casuals. However matches can be set whenever it is most convenient for both teams.