Chevy is supposedly going to bring out the new Chevy "SS", based on a revised (lightened) holden commodore (zeta 2?) platform, and there have been lots of sightings of police versions out for testing. 4 doors, nearly 400hp in basic V8 trim using an LS derivative motor. If it handles anywhere near as nicely as the pontiac G8 it should be a total hoot to drive, with better performance and handling than the dodgy chargers. Of course a mustang will still be faster but the Chebby SS will still be a very competent cross between typical cop cruiser and pursuit vehicle, able to keep up with just about anything on the road.
My Dad drove CHP 5.0 (4.9!) mustang LX pursuit cars for years before taking a desk job so it's neat to see them come back.