Pete,
The only person that I know who has bobbers in S scale is Bill Lane. One was built by legendary S scaler Frank Titman and the other one he built himself. He may have the plans for the construction if you are interested in doing scratchbuilding.
Here is Bill's page showing his bobbers....http://lanestrains.com/Caboose.htm
Also, if you do FB, I suggest you join 'S Scale Model Railroading.' S enthusiasts exists in many sub-groups and the various online S related forums have different foci. This OGR forum is largely American Flyer (post war and modern) and hi-rail focused. Personally, my interests in S are broad, so I am a member of about 7 online S groups ranging in focus from pre and post war American Flyer purist all the way to prototypical S scale modeling. So a question like this posed on FB's S Scale Model Railroading group will likely get you many more responses.
Chuck