See that picture? That’s what happens when you attempt to hide Finder.app using releaseAllDisplays. Yes, you can kind of get Finder to hide but then when you launch another application, things get confused as to who is allowed to draw what. This shows me opening what should be a menu and revealing part of Finder.app’s screen saver.
With the help and knowledge of AwkwardTV’s Eric III and Alan_Quartermain, I did manage to create a plug-in that hides Finder but I can’t seem to launch a program successfully and get it to take over the screen. My greatest success involved launching VLC from the command line and having it play back a movie full-screen. Finder stays hidden and VLC’s constant video updates and redraws prevented the issues seen here. Unfortunately, you could not control the video playback at all using the remote control.
In other related news, Alan_Quartermain has posted an advanced Apple TV coding tutorial about creating custom controls that is well worth checking out.