You wanna talk to Cliff. 
Last i read, somebody said he was on a hiatus of some kind??
I know he designed and built his own. He might be willing to share his design....for a fee! 
gr
The hitch I built is part of the trailer & trailer is single wheel. When the trailer is removed there is no sign of a hitch. Have only made some test runs so far, but all seems okay. Soon as it warms up we'll start making some short camping trips & make sure all is good, before we head out long distance.
Who knows it may turn out to be a pile of scrap metal!
