Modular Controller design

I have got an idea for the cable mess and limitations of the reprap controllers.

Why not connect all sensors, stepper motors and heaters on a bus instead of routing different cables to all of them?
Check out my idea here: https://docs.google.com/document/d/1_jqr9kyAbzlSdNBXZGIMLWlP3BdYyK0iMb3WcW60EcM/edit?usp=sharing
(I am sure that a system like this it already exists, i just haven't found it yet )
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This might also be a way to connect everything to a Raspberry PI...

Sorry about my bad english, but i guess it's better than your swedish!