One of the last Mustang related things I worked on before leaving Ford earlier this summer was a story on the design evolution of the newest version
Over the course of 2013, we published a series of sketch to production stories on each of the first five generations of Mustang in the run-up to the 50 year celebrations. Each of those can be found on this page: https://media.ford.com/content/fordmedia/fna/us/en/news/2013/08/02/mustang.html
Here are some of the sketches that emerged during the design competition for the 2015 model. I just wish that my former colleagues had chosen to share some of the other sketches to show off ideas that didn't make the cut. ?