Gonna be tough. It was made by Wise or Garelick initially. I believe Llebroc makes them for GW now.
1.) See if you get any bites here.
2.) Contact GW and see if they are willing to allow you to have one built. I asked Wise and Garelick and both indicated they did work for GW in the past but the patterns were taken back and the design is owned by GW so they cannot fabricate. Maybe GW would give permission, but I doubt it. Llebroc can't sell direct either. I doubt it will happen.
3.) Place an order with GW if they are willing to accept. It is fairly easy to install (4 bolts) if they are willing to provide.