Just came across a 5th wheel parking system developed in the US in the 1930s, then rediscovered in the 1950s, and finally reinvented somewhere in the Middle East in the 1980s to aid parking of a Renault 5!

Not great for trunk space but beats most parking assist systems in speed and you would get the dubious bonus of Continental kits in every car!

The British liking to be different, they stayed with 4 wheels but used some seriously crazy adaptive steering to achieve similar results...