Work in progress:

- Stepper controller board
Maybe I don't need Azteeg X3 Pro anymore?...

- only 3 wires per stepper! would be less
Now I should investigate if Repetier Firmware could be easily modified to disable (inverse EN signal, reconfigure STEP and DIR as input to not damage outputs) inactive tools/extruders, then i would be able to use only 6 wires total to drive 4 extruders! And they are already there, in extrusion, from beginning!
Or maybe I should look into smoothie? Looks like it have gcodes to disable tools, but I don't know about DIR and STEP signals...
but I need to add some wires anyway, for delivery power to steppers (wires already there are too thin I think), and heaters, so I need to find a way to lead them to the top plates hidden.
[sorry my English again]