I purchased my MIP from Flighdecksolutions - it comes delivered in kit form:
Here is he MIP mounted in the flight deck, the F/O RMU is a dummy, due to the LCD screen not reaching, but its convincing enough.
The purpose is obvious, but also pay attention to supporting and locating the monitors. Most builders start with this assembly, as it is of critical size for the rest of the build. In my case, as I have the shell, I can take a simpler approach, as the shell provides fixing points and support for the panel.