Comp, good points, and pretty much exactly the ones I would have made myself.
SirRob, if you want a plotline so bad, write one out, you know the very, very basics, why don't you do an outline around that. I know it won't be very clear, or long, but will at least give us some direction to work towards. As the world grows so will the plotline. We all need to start somewhere. Like Comp said, once it's down on paper we can modify it as needed.