The answer it would seem is our own government - likely a branch of the military. When I saw it again today on the back of a Transport Vitesse truck, I put two and two together. Vitesse is a major hauler for the military, so someone in Ottawa decided they needed a close up view of this vehicle, but didn't want to share that view with the rest of us.
A sticker in the window said "Do Not Tilt the Cab" in English and Chinese, so that put me on the hunt. The headlights and windshield are typical of those used by FAW, one of the Chinese big four manufacturers. The rest of the cab doesn't look much like they have to show on the internet, but it could be a new model.
The truck is new, even though it has lots of dirt under the fenders and on the engine (check out that unused fifth wheel). So I guess it is a demonstrator with a number of hours on the engine, but no work, and I will stick with FAW until the wrapping comes off.