Thats a good question.....
With all the tech around etc what would it take to "build" a MM from scratch???
Whats parts would you need that are impossible to get?
With the cost a a cab + decals etc surely it would only cost a few K..
?
If you are going to build one privately, that is paying retail prices for parts, there are quite literally thousands of individual parts that will all add up.
There was a guy in the US who has built one from scratch and he gave a figure of $12,000 by paying retail prices for parts and building one from the ground up.
Impossible to get parts (or would need to be refabricated):
Wireform ramps
Wiring loom (need to be remade)
Lane guides (the long metal strips that run around the playfield loops)
Underplayfield PCB's.