Momentary Push Button Toggling Pairs
I have been at this for over 30 years and have never seen such a switch. The article you refer to is flawed in its analysis as to how the 4 pin switch works. The circuit has a pulldown resistor pulling a pin, P7 to ground though some resistor R. The resistor and pin being pulled down to ground could just as well be tied to a single pin  of a 2 pin switch. When the switch is pressed (closed) the 3.3V is also connected to the other two pins, so that P7 is now pulled up to 3.3V and current also flows trough the resistor to ground. Its just a simple SPST switch with 2 pins on each side of the switch - could just as well be 2 pins.
No magic here, but indeed  some sleight of hand.