Ed, If you can actually make something like that possible, I definately think it would be a useful tool for law enforcement. I live near Houston, TX and almost every day there is a high speed chase on one or more of the freeways being broadcast on the news.
No special equipment?? That would be a plus too, but I`m sure people would be willing to pay as most times it is a stolen vehicle in the chase.
Good luck. I hope you get some more feedback - let us know how the development of your product goes!