My wife and some of the other therapists have been using the device at work. It's been super successful with the kids. The one child who it was made for has been showing progress they've never seen from him. It's exciting when a project actually ends up helping people. Since they're using it so much, they've given me a lot of suggestions on how to make it better. Like, "Can you make it so the wires aren't everywhere?" I've actually been making a lot of progress on the second iteration. It's been whittled smaller and smaller and idea after idea has been considered and thrown out. After a lot of prototyping, this is the next version:

It was actually laser cut today. I plan on putting a handle on the front to make it easy to carry (which I forgot to include in the drawing). The sides will have 1/4" inputs to make it easy to use with existing therapy inputs and a rotary switch to allow the inputs to be configured. With this, the therapist wouldn't have to do anything to switch the video except turn the switch. Additionally, this can be used to configure multiple inputs to activate the same video. This was not possible in the previous version. Finally, a DC jack was added which can be used with a 12 V battery pack I bought, or a 12 V wall wart.