Here's a simple video rig for Smartphones that offers two Cold Shoe mounts and several 1/4" threaded mounts for attaching a variety of accessories. I was intrigued by this as I believe it could be an inexpensive way to build out a handheld rig with a small monitor for use as a director's monitor.

Especially if you consider how much the SmallHD 501 / 502 monitors look like iPhones, this rig could easily be modified. The two cold shoes could be a clean and simple way to mount up those wireless video receivers too.

iPhone Video Rig Cold Shoes Threaded Mounts