Rebar (assuming it weathers well) trellis like this? The "roughness" of it would not be a design problem. I like the way it is offset from the supporting structure.
Beautiful, scrolled trellis, but use old wrought iron door...now this is the kind of trellis that I'm talking about, perhaps leaning against my shed side! :)
large scale decorative iron trellis for a house wall
French Trellises by Trellis Art Designs
A diamond-patterned lattice surrounds a wall fountain.
add pieces to wrought iron trellis plus the wrought iron shelves
High Quality Metal Garden Trellises #4 Wrought Iron Garden Trellis Metal
Wrought Iron Trellis
This Scroll Wall Trellis functions beautifully against a wall, positioned as a freestanding divider, or planted into an oversized container.