Completed tutorial along with a few other explorations (in the Swift3 branch). Getting the touches to pass through from the SpriteKit overlay into the SceneKit required making mods as described in the comments in the tutorial page.
In this tutorial you will learn how to layer SpriteKit content on top of a SceneKit scene. I will also show you how to create dynamic SceneKit materials by using SpriteKit scenes.
Source files for the Tuts+ tutorial: Utilising SpriteKit content within SceneKit