Watching the video frame-by-frame, the device being placed into the communicator does seem to be an iPod Nano 7th generation (the outline of the home button is visible, which is not present on Android phones). There are two pin holes in the left side of the communicator body, which line up with the volume/play switches - one of these could be used to hit the center button with a paperclip to play and pause video. Through this mechanism it would not matter that the iPod OS places the touch screen play button in a location obstructed by the communicator faceplate (the iPod OS is incapable of playing "vertical" video so the touch button does not relocate via screen rotation to the lower edge of the screen as with iOS devices like the iPhone). In the video, the back face of the lower center button of the communicator is domed on the back (does not match the left button), hinting that it is loose in order to press the iPod home button and wake it from sleep mode (the play button does not wake the iPod):
However! I have also seen a photo from someone connected to the production that showed a very small Android phone in use (the Posh Micro X S240):
In the props video above there is a single hole visible on the right side (closest to the camera) of the communicator body which lines up perfectly with the power/wake button on the phone.
In fact the two holes on the left side are better aligned with the volume buttons on the Micro X than the play button on the iPod. The phone is a bit wider than the iPod, which could explain the need to manually grind out the area around the volume button access holes as seen in the picture above. As an aside, Android is more user-friendly than the iPod OS when it comes to video, supporting a wider variety of compatible video formats and being capable of vertical video playback.
BTW the button access holes were visible on the communicator that was on display at the two recent conventions, though the one on the right side barely showed up in one of the photos I took in Vegas. Anyone have a better shot?
So it seems the communicator has used at least two different devices so far. I wonder why? The iPod Nano discontinuation news didn't happen until around the time of STLV. Perhaps they serve different purposes? Video is better on the Android device, but the iPod has a good photo slide show...