I can't help but go back to DFRPG if just for the magic system. Ditch the organizations and all rules associated with them. Get your players to help you develop fluff to fill in the power vacuums. I think if you tell them up front that this is a game built on the DFRPG rules, but without any of the story, you'll be fine. That's how Ttory_Seller's "The Last Escape" was billed, and despite half of us being Dresdenophiles, we're all having a great time.