Paul, I agree completely. I too am a bike patrol officer and the chief-cook-and-bike-repair guy for our department. I look after a fleet of about 18 bikes.
We've had excellent luck with the Trek line over the years. We've tried a couple of Smith & Wessons, and had to replace nearly all the bits within a year. Really cheaped out on the spec.
I just looked at the Fuji jobs our local Law Enforcement store is carrying; pretty much the same.
That being said, there is no great shakes between a "police" bike and any other, besides the decals. Most of them have rather stout frames, as bike cops are rather....stout. I carry a good 12 pounds of extra stuff.
Single speed? What universe does this fellow live in? I carry 12 pounds of gear on my body, and we have luggage carriers filled with a variety of police-y items. Like Paul, I need every gear on the bike.
I have been buying the Continental Town & Country tire for about 6 years now, most all the others we've tried have poor service life or are flat magnets.