FWIW here are the trailers I have and aren't sure which kits they came from. At least one came from the 1960 Ford pickup kit but without the sides. The black single axle is shorter than the red dual axle which has a tool box and tire pole added. The blue one is a modified dual axle made to look like an English Don Parker trailer (the cycle fenders are from '32 Ford 3 in 1 kits) and the gray one is the MPC Mako Shark version of a tilt trailer which was identified in a previous thread.