Wow, a mythology mod would be killer.
I can imagine Amazons and Gorgons being implemented pretty easily, just off the top of my head. How cool would it be to ride as a mount Pegasus or one of the Mares of Diomedes??
This might push it for you guys, but I think a "World Mythology" mod would be absolutely insane. One faction could be Greek, one faction Egyptian, one faction Norse - basically, Age of Mythology M&B. You could even use AoM as a place to get unit ideas.