Solid Works - never used it, but our design department came very close to buying it for their 20 or so designers. It looked nice.

OK, so how about this(at least at and below the waterline):

1. Assume ALL cross sections are a known 2-D shape that you can caluclate the area (and thus the integrated volume over length) - such as an ellipse (or actually semi-ellipse - I am very pro-ellipse - it's a great shape!).
2. Assume that the center of the ellipse is always at the waterline, Thus the (semi) ellipses start off vertical and become hroizontal, and at midships, they transition to a perfect (semi) circle.
3. Now there are only 2 "scalable" dimensions for each section as you transverse from bow to stern, the major and minor axis of each ellipse (sounds easy).
4. If you keep the displacment constant (say 100KG per hull - it's weight and one sailor), and a known prismatic (say .67), then you have defined the central "ellipse".
5. Now the hard part - vary the height/width of all the ellipses in a uniform manner, maintaining the displacment and prismatic - rocker will be a fall-out. Enter it into a spreadsheet for various hull lengths and you can have Pro-E or others gnerate and loft these sections for each hull length. Then you can calculate the actual hull weight (based on a skin thickness, wetted surface etc). then you can vary prismatic again, or displacemnt or whatever and you now have your "rubber" CAD produced hull. Try heeling it a little to see what happens to wetted surface, etc...

What good this does, I don't know, but it was a fun mental exercise. Then above the waterline is realy tricky with reserve buoyancy, windage, "wave piercing" ability, and other considerations.

Anyone want to do this? Maybe I'll give it a try.