With the new Boeing 787 where Boeing has provided the capability to swap engine types if the aircraft goes to a new operator quite quickly, I'm wondering if there are any **interchangeable flightdecks**? 

Say that you might have a legacy 737 for southwest, but an entirely different cockpit layout (containing the same capabilities) for a company which operates Boeing 787s as well, since the similarities would make training easier.

I know a similar project was done on the DC-10s becoming MD-10s, as well as some Saudi MD-90s to be similar to MD-11, but both of these were long-time consuming projects. 

But I'm wondering if there are any aircraft which have this possibility and if not, why not? I'd see it as an opportunity to Boeing to have a 787 flightdeck shared with say the 777.