Eons ago, Loggers World had a story about a Peerless or perhaps General I can't remember which, "steerable trailer." This was back in the early '70s. All I remember it operated with a toggle switch and was only used in the woods, not on the highway for long loads. When you reached pavement, you locked the wheels in "normal" and it was a standard extendable reach trailer.
I can only assume it was a marketing failure since after the article I never saw or heard of one. Possibly it was just an experiment. It was designed for hauling poles out of the woods. Findley had a couple of photos of it in operation. Anybody have all their old LW papers?