Thanks guys. I have been searching for a couple days and I have only found a few photos. I actually found some old brochures for these trailers, listed on E-Bay and some other E-Bay knock off. Havne't bought them, though they would be handy to help build a nice replica of such a trailer.
The only brand I have found so far is Hobbs Schonrock. There may have been others.
These photos aren't much to look at. Can't actually see the winch cable and pulleys all that well, but they did exist. I'd like to build one, if I could.
It's an easter egg hunt!