Well, with a B&G, you have 2 choices. Get spendy and buy a SS cage like Expandable Habitats or Animal Environments. They will likely last forever.
Or buy a double macaw cage from one of the China 3, knowing you will need to repair welds and have it repowder coated here and there (or keep buying new ones).
There is a guy whose company is called Reed Seed, who goes to some of the birds shows. He often does have amazing deals on HQ. Last year he was selling double macaw cages for just $399. If you let him know ahead of time what show you will be at that he is, and pay for the cage, he will bring it and then you pick it up there. No shipping so a much better price.
http://reedseedco.com/