I am new to ATP, and am just cruising around the site. I am surprised that I don't see examples of these posted. Cattle panel - found at farm supply stores at about $20 each make great arch trellises. The panels are 16' X 4'
I pound 18" rebar into the ground, leaving 6" above, and wire the cattle panels to the rebar, using 3 pieces of rebar on each side.
I have 6 of them in my kitchen garden. One for the entrance, two on each side and one in the back. I use them for cukes, beans, tomatoes, and this year I started a few grapevines.