Would highly recommend Katco Stairways, (
www.katcostairs.com), out of Hampstead, NH. He does custom stairways, rails, balusters, etc. We actually went the opposite of you and got rid of wrought iron for traditional cherry rails and balusters. It came out amazing. Note that when we used him about a year and a half ago, it was about a 4 month wait from quote to install....he was that busy.