Yes, there were quite a few. But the link I posted wasn't the initial one I found - PRR 495601 is little more than a flat car with an outhouse in the middle, but over one of the trucks, an most impressive array of feelers. Also the NYC had one with a pantagraph to document spots with clearance issues. Both can be seen on p1928 of Train Shed 26.
Just a few pages before the Y4 type scale test car that I'm working on.