I bought some cheaper regular steel threaded rod to get right before bending the stainless. The first one I bent came out pretty well, although my method of bending was pretty crude... beating it with a rubber mallet while in a vice next to a big socket. The second I put in and tried to bend broke, I tried again a few inches up and it broke again. So, I went and got more rods, and picked up some pipes to slide over the rod whie bending.
I then decided to make a bending jig for it, and just bend with the pipe. I routed holes for the bits to sit in, and the whole thing is bolted together using the broken threaded rods. I put that whole thing in the vice and bent it, resulting in a much nicer looking radius, and no marring from the hammering or the vice.
I think I will be able to use just the washers on the rod without welding, which would be expensive and may screw up the finish. I used 5/16" fender washers and threaded them, so they hold when bolted from behind. The washers will be flush with the surface on the speakers and wall plates.
I think I will still rebend the top bar, as the one bent with the jig has much smoother bends, and I'd like them to match when starting with the stainless steel.