Build a Custom Trellis/Arbor

I want a sturdy wooden trellis/arbor for my garden to arch over and span two raised beds at 90 degrees to each other (they are farther away at the front, and closer together in the back), top of arch 6' or more above ground (beds are 2 ft. tall). It should hold climbing heavy vegetables like tomatoes, cukes, melons or bean vines, with 3 or more arches and crosspieces for stabilization. Willow would be nice, if made sturdy enough. Trellis ends could fit into inside edge of each bed spanned. Removable for winter would be nice, but not essential. I can provide exact dimensions. Needed for next spring (April-May 2018).