Another aspect of multi monitor support that might be of interest is the main menu GUI. I really like the new GUI, however in my diy B738 simulator where I use three 65 inch tvs, it is very hard to use the GUI as my view of monitors are limited. To select the fly button I have to poke my head out the FO window to see what I’m doing.
One solution that comes to mind is to have the GUI as a webpage which can be accessed on a tablet or similar, instead of having to add an additional monitor just for the GUI.