You don't need to be arty - be scientific about it! A good way of designin ga body shape is to use overlapping elipses and then draw around the outside to get the overall shape. What I'm getting at is that a Les Paul, for example, is made up of two elipses (one for the lower bout and one for the upper bout) with a third elipse touching them to make the shape of the cuttaway and two more coming in from either side to touch the first two to define the shape of the waist. I guess it's a bit hard to explain without drawings - I'll have to see what I can come up with.