As much as I enjoy filling my inbox with messages Ima start responding here.
Steve Thomas is right. DK monitors were 19". The reason I thought they were a 20" inch is because they were a 19" Sayno EZ-20. And that is what I remembered the EZ-20. I'm not sure what direction you are going in but by your trailer I assume you are going with an original cab and not a Donkey Kong run by a computer. I don't know how rare they are but I would keep looking around to see if you can find a 19" monitor. It took me a while to find my Nintendo coin door but I was glad I didn't put anything else in its place. Haste makes waste.
Good luck. I'll be watching this build.