So, this isn't contemporary and it isn't really a SWB. The front and top are what I am after. The rear is kobra, but as this is my first paint attempt, the crude line down the arch represents the bulge and the scribble hides the rear vent on the SWB.
Kind of what I am after as an alternative though. Ideally, the top would taper down slightly at the rear so that it isn't so obviously Z3. But I could live with that.