Cost of shipping a dimensional object wide makes this something to make on site. A roll bender, 2 steel pipe and 6 pvc pipe are the main materials. The larger the diameter the higher the yield in the area.
"Even better idea for a cucumber Trellis. This way i can make use of the sides of the beds I've already built" (and do this for melons too - use old stockings to put them in a sling if they get really big.