[Albert1234]

4 wheel steering using 4 wheels that tilt is a good idea but I wonder if it is the only way to accomplish the task.

GM promotes their Quadrasteer by saying it allows easier parking at low speeds, and easier towing at high speeds. But the downside is larger rear fenders and wheelwells that intrude into the bed. And, the system is expensive.

I'm mainly after easier parking. I don't really care about easier towing. Couldn't Nissan reprogram their active brake limited slip and vehicle dynamic control system to completely lock one rear wheel while allowing the other to spin (at low speeds only, and when the driver activates a control). Then the rear of the vehicle would slide sideways (like a skid steer bobcat). The front of the vehicle would turn the normal way (with tilting wheels).

You might not be able to turn both ends of the vehicle at the same time (as you can do with Quadrasteer), but you could selectively turn either the front or the rear.