I got a cheap mini ATX case and turned it into an enclosure for all the electronics. 

The front also has a few usb port and buttons. I will keep one USB port for the Arduino, insert a voltmeter for one of the power supply and add 2 potentiometer knob to adjust the voltage and the speed of the spindle. One of the usb port will be removed to insert the spindle switch. The back will have the two power supply outlet with a switch as well as 5 outlets for the motors and the spindle.

The main fan of the case will be wired to the +10V of the spindle controller.

Here's a first snapshot with the components before wiring