Have any pics of this? I am guessing its just a belt that is bolted on each end with no center support?
I agree with this. My trailers do not have fenders on them, but I typically am hauling equipment so I dont worry much. If I were going to haul any cars, I would put some on.
What about building "stake" pockets and attaching the "stake" to the fender. Then they just slide up and out. Could be a simple 1" tube with a 1.25/1.5" pocket. stick a pin in the bottom of one so it doesnt bounce out. Most of the time, only the driver side is removeable, since they are typically for allowing someone to open a car door.