I've been spit-balling again, on the backburner, about framework materials. Ideally, I'd scrounge for it. But, in keeping my options open, I've looked into things that can be bought.

Would you guys think T-posts or U-posts would be an adequate substitute? I'd bolt them together, with whatever amount of overlap is necessary to get the correct strength & rigidity to the frame. Holes drilled where appropriate.

Everbilt 3 in. x 3 in. x 6 ft. Green Metal Heavy Duty Fence U-Post 901156EB at The Home Depot - Mobile

Everbilt 1-3/4 in. x 3-1/2 in. x 6 ft. Green Steel Fence T-Post 901176EB at The Home Depot - Mobile