I have seen several tutorials online on creating non-rectilinear windows in WPF using transparent images and no Background Brush.  Oddly enough this leaves you with the issue of not being able to grab the title bar (since it does not exist) and drag your curvey new window around.  I initially found no workable solution for this and even asked around to those who are wiser than I; no answer.  By rephrasing my request to google I found the following:

1. Using Expression Blend, highlight your Window class.  Add an event handler for MouseLeftButtonDown
2. In Visual Studio, add the following code to said event handler:

private void ExifViewer_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
   DragMove();
}

Fantastic.  The plumbing was already there, easy, and obvious, but because this is a new platform I could not find it.