I wanted to try my hand at creating an unchained version of the zen archer. As I went through it, it seemed to go a bit beyond what an archetype did, so I made it into an alternate class for the monk, in the same way as the ninja is to the rogue. I haven't yet written up which Ki Powers will be available to the class, but everything else regarding the class should be done.
Here's a link to the google document: Unchained Zen Archer