There used to be a guy at a truck stop off Centennial and the QEW who sold scanners and batteries, it was many years ago and it was very expensive, I wonder if he is still there.
As mentioned earlier in the thread that the OPP are digital, from the Charlton Street tower you will hear coverageof Provincial roads from Mississauga to York Region to Cambridge to Niagara.
Outside of Metrolinx I cant think of anything else digital.