Let's define the rules of the game:
Feature Length Project - 75+ minutes
Multiple Geographically Separated Filmmakers - how many minimum? 5, 10? what percentage do they have to contribute? i.e. no more than 25% of running length can be filmed in one location?
Traditional Film - I read that as relatively linear story featuring primarily the same characters throughout the running time. Any other distinctions there?
Style - I'm assuming we are excluding animation as a deliverable. Any other styles / mediums that would exclude a project?
How about a global phenomenon? Like the world is going to end and people from all around the globe are trying desperately to travel to a secret underground bunker, or there's an alien invasion, zombie apocalypse, you name it.
Each segment would be about people from that particular state or country reacting to and coping with whatever the phenomenon is, this way each director could have freedom in their work. The overall style and technical requirements would have to be agreed upon before filming, and once it's all in the can, the post would be done by one party.
I like the ideas NickClapper posted before, they could definitely work.
This way the movie would work as a whole piece, and not just a collection of shorts, and each segment would naturally have a different setting and different characters.
Now that I started thinking, there are many possibilities for the plot, What about this: The main characters in each segment have one thing in common, at the exact same time, they all realize that they have superpowers.
Is it all a coincidence, or are they all connected somehow? Maybe they are all products of a top secret government mutation test. Maybe they aren't human at all.
Will they all get together and form a real life Fantastic Four/The Avengers? Do they even know about each other? Will their superpowers be revealed to the world, or will they keep it a secret?
The superpowers could be something that wouldn't require too much CGI or anything, like invisibility, practically free, telekinesis/mind control, time travel/dimensional travel etc.
Something like that could result in some interesting stuff. For example when one of the characters realizes he/she can read people's thoughts or even control them, will he/she use it for his/her own personal gains, or use it for common good?
Each segment could even be a different genre, like maybe one of the characters is a housewife, and that would be more of a dramatic segment, one could be more action oriented, one comedic etc.
Or they could all be within the same style and genre, something between Chronicle and Kick Ass.
That would be a pretty high concept idea, that would benefit from different filmmakers from different parts of the world contributing.
Let me know what you think.