When I bought the Prius C out salesman just drive 40 miles to go pick up the car from another dealer and drive it back.
That sucks. I would have raised hell for putting excessive mileage on my brand new car. I've seen 4 different Tundras with trailers at my local dealer for dealer trades. They go anywhere in CA to trade. They do have a non-negotiable dealer trade charge of $400 though.
I've seen dealer cars traveling in convoys many times. Some dealers also let you test drive any new car on their lot. Mileage just isn't much of a concern to some dealers I guess.