I needed a way to mount my iPad Mini in my 2005 Prius, so that I could use it as a better Navigator and audio source. The products I found commercially available were annoying solutions, so I decided to make my own. It clips to the open door of the little CD storage hutch below the radio.
Included STL files are for an iPad Mini with a rubberized wrap case. This can also be used to make an iPhone5 mount.
[Update: Added speaker ports. Refactored to keep device dimensions together]

1) Tweak the settings in the OpenSCAD file to match your iPad/iPhone/case combo.
2) Compile and Render to CGAL (F6).
3) Export to STL.
4) Slice.
5) Print.