Limit Switches with LED's

[Jonathan]

If you're happy with just one colour LED - i.e. red when the switch is pressed, off otherwise, which basically tells you the same thing as having red/green, then it's a lot simpler. Just put an LED with series resistor in parallel with each switch.
Since you will use normally closed switches, when the switch is open (pressed) the supply voltage to the switches is now present across the switch, so will light the LED. If multiple switches are pressed, the same is true except the voltage is now divided by the number of switches that are pressed so the LEDs would be dim, hence you need to choose the resistor values carefully. If you're happy with that limitation then this is a simple solution to implement, but for the sake of one extra component Robin's solution is better.

You could instead do it in software - make a box on the gui turn red/green for each switch.