Wood is a viable option and affordable .. I'm hoping a local engineering / metal fab business keeps 4130 in stock or will order it with their next load.
We have a aircraft business in town , Coulsens ,who keeps and repairs flying water tankers and business class helicopters on the outskirts of the City with luck the firms that supply him have Chromoly stock.
The Canada online metal supplier I priced the Chromoly at offers small batch deliveries with a $5 per cut fee. In my case that would be two 3.5 sections and two 2 foot sections.
Wood friend or foe
We are in a logging town with spruce fir and cedar in the hills.
A wood frame would be / could be roadside repairable. Cedar being so flexible when it breaks it splinters like intertwined fingers so it can be jammed back together and bound if it where to break.
A major problem with cedar / wood is the mounting brackets , with tube I can buy adjustable joints with wood it would not be so simple.
But maybe a combination of the two will work together
I want it to be something simple employing store bought swivel joints , this next trailer is what im after.
Although in my case the panel will end at the middle of the rear wheel.
I will know more about the metal price / availability when speak with a few local engineering firms.