New version - http://www.thingiverse.com/thing:1697237
The mount is designed around my LG G2 in an Incipio case. Modify the clips for other applications.
The pieces were printed in PLA at .2 mm layer height and 100% density. The center mount piece is tapped with M3 threads. Printed pieces hold threads surprisingly well. M3x25 socket head screws hold the clips to the center piece.
An M4x45 flat head screw holds the mount to the transmitter bracket. A nut secures the bolt to one side of the arm. I'm not entirely sure it was necessary but I didn't want the screw turning. The well in the thumb screw holds an M4 nut.
iris_phone_bracket1a.stl has a simple bracket with a shorter thumb screw. It works fine, but it just didn't feel secure enough.