One of the issues in making a game like this work would be the large number of characters we'd need that are, at the end, kind of bit roles. Sure, some people will play location staffers, but there will be a lot more models and managers. You know, for reasons. :)
So, we probably need a method to cover those characters (We'll not get enough players to cover it). In a traditional RPG, there's the GM to handle them- but, if we don't have one, we should have a system, even if it's just a spare OOC thread where people can put minor characters in the game world that people can use. They don't need to be complicated- one or two lines usually covers them- and people can just sort of use them as needed.
The other thing that would help, I think, is some sort of plot. Something to hang thigns together. Otherwise, it's just sexy time at the modeling agency, which sounds fun, but honestly won't hang together for long. It doesn't take much: just a simple story. The agency gets a contract for a big show, and we have to put it on! The Agency's founder just died. Will we hold it together? Is it an older agency that's fallen on hard times, and we're going to bring it back? You know, something we c an hang everything on, even if it's just *mostly* sexy times with models and rich dudes.