Visible crew/equipment: Just as McClane jumps down the cab of the semi, there is a quick shot where the camera shadow is visible on the semi. (01:43:05)
Visible crew/equipment: In the scene where John and Matt are in the middle of an alley, with Matt using the mobile to locate the power hub, the crew can be seen from the reflection from the glass behind Matt.
Chosen answer: Looks like a standard 5 mph speed sign to me. You can't read too much into that. In addition though, Bruce Willis has already stated in a few interviews that he'd be more than happy to do another one.
XIII