Not sure about the difficulty level for installation, just running the wires and building some suitable housing for the cameras, BUT...
But the price of admission!!!
Hardware Platforms - logiVIEW-SVK
it is about 7,500 euros, so about $10K!!!
Of course, it is just one place - I hope that with time, that technology will become mainstream, and the prices will come down drastically as it is good not only for parking but also for the blind spots around the car going at 60 MPH... My first VCR was about $300 at Wal-Mart back in 1991 - now you can get DVD player for $30...
BTW, why are always coming back to 60MPH? like nobody goes faster, or what????