The clip employed an open source ("crowdsourced") development method, one which bands like Radiohead have also used, to interesting effect. Fans were invited to submit online drawings - via The Johnny Cash Project website - based on provided stills from the Man in Black's 1973 film, The Gospel Road (the story of Jesus, told Cash-style...which I, a diehard fan myself, can really only recommend to those who would classify themselves as such). The drawings were then compiled, creating a compelling piece for an artist who knew a thing or two about powerful videos.
The video is completed, but you can still make some fun drawings. Do so, and watch the final product, here.