I know this is slightly OT since the mod is not actually done on the trailer itself, but to the tow vehicle. Reason I am posting it is that I made the mod to facilitate long travels en route to camping destinations.
My RV mods: Add a 22 inch TV in Tow vehicle
I wanted to put in as big a tv as possible in the truck.
It may even be possible for people to use the TV in their trailer for the same purpose, it would only need to be switched from one location to the other.
I am thinking of doing that as well.