It occurred to me this morning, while I was driving to work, that there are a few more important elements to the setting that I hadn't earlier articulated.
The world is divided into two parts. There is the part where the PCs are from and the part where the PCs are adventuring in. That's not to say that all of the PCs have the same homeland. Far from it. The important part is that the PCs are far from home during the aventures. They are always outsiders.
It also occurred to me that we're going to have to strike an important balance between too much and too little information about the setting. The game will benefit from a strong and well-directed setting. However, too much information can only serve to distract players from what the game is really about.
What it's really about: Becoming rich and famous before you retire.
If all the game revolves around the rich & famous hook, then I don't see how we can possibly go wrong. (yet)