This is something I came up with a while back, but it's kind of similar to the "Restaurant: Freedom" idea.
No single fast food place has the best of everything. McDonald's has better fries, but the Carl's Jr. burger is better, Dairy Queen has awesome blizzards, etc. etc. Sometimes, you want something from one place, and something else from another, but it sucks to try to drive all around to get all the separate things. So, what about a single giant fast food combo restaurant, where you can order items off the menus of any of the restaurants? They'll each have their own separate kitchens, so that they cook the food separately, but one order window so you can create your own ultimate combo meal.