Renault do one themselves. The part number is a few years old but - 77 11 225 819 is the required number and the price shown is £346.38
Anywhere that makes up the type of exhaust you'll see any night on the @rse end of any Corsa or Saxo will make you up a stainless section, but I've no idea of price.
I know of a compnay called Longlife exhausts, they have depots all over the country so you should find one near you some where. They custom build stainless steel exhausts to suit what ever car you have. I had a quote once for an escort I had. Was about £120 for a back box, which isn't bad as it's custom made and fitted for you, but then you can add to that as they do different style tips for various prices, but that was the only additional cost involved. I opted for a PECO Powermaster in the end off a friend cheap so didn't bother getting the longlife one.