AKJ:
If the Intensity of the devices you want to connect to the 5V pin is not higher than 40 mA, connect many cable to the 5V pin.You can always turn any other pin to a 5V power output.
The 5volt pin is the power rail of the Arduino (5volt Arduinos).
It has nothing to do with the 40mA absolute max limitation of an I/O pin.
You can e.g. draw ~450mA from the 5volt pin(s) of an Uno when powered from USB.
Not a good idea to power things from an I/O pin, unless they draw very little current (<=20mA).
Note that there can be some volt drop when doing so (not the full 5volt).
Leo..