You might want to look at Karavan trailers, currently being sold at Sam's Club as well as other places. Inexpensive but seems to fit your requirements. All sides fold down if desired, and are removable, including ramp tailgate. Only two things I added was to change out the fixed leg jack stand for a flip up, and add 6 tie-down I-bolts.
I bought their smaller one, 12' to haul my mower and/or SxS. It's also used for numerous other chores like hauling logs and brush as needed. I think I paid a little over $1K for the 6'x12' size.
Now - its not a Kaufman or PJ for sure. But then, I already have a 20' PJ for heavy duty tractor hauling, etc.. Don't need two Cadillac trailers...