Fluid Motion gets all its stainless steel custom railings from Bolton Steel in Vancouver, BC. https://www.boltonstainless.com/
I try Bolton first.
If not, any good marine canvas shop that does Bimini work should be able to make you up a set. I’d give King Marine Canvas in Seattle a call too. If King can’t help they could probably steer you to someone who can. https://www.kingmarinecanvas.com/
Good luck!