Actually you can have 2 Displays with the PI hardwired unit.
http://www.progressiveindustries.net/ems_rds.htm Currently I have my display in the hallway next to the switches for the slides & awning. I plan to add one of these to the convince center. Right now I have to enter the trailer to check the status. I like having the display inside but during setup it is a pain to have to enter the trailer to check the status.