I have never had a soprano saxophone. I had the insane idea that I might print a soprano saxophone cone in sections and experiment with boring holes in it and so on to see what I might come up with, so I printed a small section of the top of the cone where the mouthpiece connects, but I needed a mouthpiece to see if it was going to work.  

I discovered a wealth of information on the site http://sax.mpostma.nl/EN/ which has a lot of measurements that are really useful on existing saxophones and mouthpieces.  

I used this site to create a mouthpiece using freecad to rough out the chamber dimensions, then filled out around it with something I think is a fair shape for the mouthpiece. If you print this, get a thumbscrew at your local hardware store for the ligature, then print  http://www.thingiverse.com/thing:46980 (the soprano reed) you will be able to have a fully printed soprano mouthpiece.  

Also published on http://www.thingiverse.com/thing:991449