My dad glued up some pine boards and then we cut out the general shape (using templates from my CAD model) using a really big band saw. I then used a large file and a sander to get it to the final shape. I made cardboard templates to help be get the corner radii right and keep things consistent.
The Finished Product
The final tank won't have a pointed front because it will be cut out for the frame tunnel. Also, the seat will be trimmed to match the profile of the tank where they meet. The flat part of the seat buck is actually a little long so we can trim it to fit.
Here is the lonely engine waiting for a bike to call home
and the three tanks that didn't make the cut