I've never had the urge to own a cop bike, but I did once, by accident. My mate Jeff at Ace had a Suzuki GS750 going cheap, and as I was into GS1000's at the time, he rang me to see if I wanted it? As far as I'm aware, it was either an ex-SA cop bike, or a prototype that the cops had for testing, but never put in an order?
Someone had taken most of the cop regalia off it and painted over the white frame (poorly, with the engine still in place) but it still had the cop speedo/tacho on it's special bracket, which I still have. It had done next to no miles on the odo, and as Jeff had ratted the OEM ignition I threw a Martek electronic ignition into it and was amazed that I could wind the idle down to a steady 200 RPM. I sold it to a guy who was going to "Civilianise" it, by removing the long rear fender, crash bars and some other bits. They were nice bikes to ride, but not sure if they were ever brought into service by the cops?