As I was leaving the Army, the MP Corps was in the initial stages of fielding the M1117 Armored Security Vehicle (ASV). I think you'll find it pretty much offers what you proposed.
That’s very interesting. I’d say next they should make a smaller version that holds somwhere around the neighborhood of one passenger max. THen make the turret remote controlled by the driver so that the whole vehicle and weapons can be operated by one person in a pinch.
Maybe something about the size of a british “ferret” armored car.
Also, replace the dual 50 cal guns with a modern gatling gun.