Examples of using ImplicitCAD's shell() operation which allows you to make an object a certain width from the boundary of your original object. Look at the *.escad source files to see exciting new features of ImplicitCAD's Extended OpenSCAD format.
See the README:
PS. People will be releived to hear that, since the last examples were posted, ImplicitCAD's extopenscad parser has gained support for OpenSCAD modules. And it supports recursive ones!
Just install as described in the README (make sure to install the development branch, or this code may not work), then run extopenscad [filename] -- it will produce an STL file with an intelligently chosen name, if there's a 3D object to render (or an SVG if there's a 2D object). View the resulting STL in your favorite triangle mesh viewer.