I don't think you will have much trouble finding the hardware....but it won't work for coats....they are too heavy for a rod without support on both ends.
Perhaps a rod with a bracket support from the ceiling of the armoire would work? Or do as the old timers did....hang the coats from big hooks on the back wall of the armoire.

You are right about the coats being too heavy ... this particular piece of hardware I saw was also supported to the ceiling of the closet. I have never seen anything like it, but apparently it was common place ... at least that is what the dealer told me. I would use hooks, but i want to hang many coats and alot of the coats are "formal" and need to be on hangers or they will lose their shape. THanks!

They used to hang the coats on hangers and hang the hangers on the hook...can't hang too many that way....but some.