When I was a kid, the local Schwinn Cyclery sold cross brace handlebars for the Schwinn Sting-Ray.
That was the beginning of the BMX movement of the 1970’s.
One of the other local bike shops sold a lot of Wald aftermarket products, and I seem to remember that they also had a braced long horn SB bar available at that time.
So, I’m not sure, if they ever really stopped producing them?