Alright, I went to 2K support to see if they could fix this issue. Just got a brand new computer and tried this again with 22 Zulus all the way down to 10. Where they all crashed.
Here is the message:
Hello.
The game crashes when you select the same leaders, there is usually a crashing point in where you select more of the same leaders in the game. This happens to all Civilizations in the game. And the crash point is usually at 8-12 leaders of the same Civilization.
For an example, today I tried playing a Continents map on Huge with 22 Zulus. Which is 22 of the same exact Civ, I did this merely for fun of course. But a few seconds after, pressing start and going into the leader screen at the Zulu, it crashed. So I had to restart Civilization V, since time I tried 16 Zulu on the same settings, it crashed again. Then I tried 14, where it also crashed. I tried putting less and less of the same leader until eventually it worked with 7 of the same Civ, which is unfair and to me boring.
I published a thread about this issue sometime ago, although no one seemed to have an solution to the problem, only that the crash point for them we're 8-12 of the same leaders on any sized map. This is at CivFanatics and the thread is here:
http://forums.civfanatics.com/showthread.php?t=533338
Please have a good read of this thread and understand that multiple people are experiencing this problem, not just me. My graphics drivers are fully up to date and Civilization V can run the recommended specs.
Once you have read the thread, please start investigating this issue and maybe include a patch for Civ V, although with it's other issues. (Such as Polynesia not being able to use Trade Routes over the ocean until it discovers Astronomy, even though its units can embark and cross oceans immediately.)
Thanks.