Suggestion: make it a GoogleTV / AppleTV app so users can set it up in a few clicks and transform any screen laying around into a sign.

I built https://signagesync.app for my cafe. It can be used to create a video wall (combine multiple screens to make a bigger screen).

I think BIGWORDS.PAGE would be a great companion to a web browser app on those TV devices. I haven't found any good web browser for AppleTV, but if somebody has a browser/kiosk app that let's you send a URL from your phone, that would be really great!

Unfortunately Apple TV doesn't support WebView. I'm procuring a second-hand device so I can test my app there. I'm thinking of rendering it on the server and sending a series of images. Not sure of the cost, though.

Shameless plug: I made Theopenpresenter.com that can do this. You can find the app in GoogleTV (not AppleTV due to browser limitation). And you can control it from phone or anywhere else.