Rear wheel steering vehicles are prone to massive, uncontrollable oversteer. You'd need a stability control system that can take over the steering in order to make it human-drivable. I can only imagine that it worked with the above mentioned vehicle because it appears there was only one rear wheel, in which case it should be easier, but certainly not equal to front wheel steering. Also, I have my doubts that the above mentioned vehicle would ever challenge modern cars in terms of cruising speed and lane-change ability.