I often make neckerchief slides for new cub scouts. One asked for a BB-8 neckerchief slide. So I used someone else's model and turned it into a neckerchief slide. Since I had already found a nice Stormtrooper model, I made one from that as well.

Note that the "helmet1.stl", "NEW_DROID_BODY.STL", and "NEW_DROID_HEAD.STL" are not my designs. They are cool designs that I found elsewhere.

The Stormtrooper model came from http://www.thingiverse.com/thing:325431/

Note that the STL files for the BB-8 models are very large, and so the model takes a long time (and a lot of memory) in OpenSCAD to regenerate, at least on my computer.