Its surprising that Pennsylvania is the only state with this procedure- that is how I knew about it. I couldn't find it for Calif either- but there has to be a way to motion the court of common pleas to hear a criminal case, in other words force the DA office to take it- again it is very odd if PA is the only state with this.
I will try to find what I can on
www.findlaw.com
you could directly call the DA office, or the general court system, and see what sort of answer you get.
I can tell you that in Penn. any crime may be denounced vis the "private criminal complaint"- I remember a case of homicide by a cop that the system refused to prosecute, the victim was a black man, so a local black rights organization pursed the matter and forced the issue to trial- there may have even been a conviction in the end for manslaughter. (not sure on the outcome)
anyway, what about "unauthorized possession of vehicle"- a misdemeanor?