Watching your progress, but can't offer any assistance. I am assuming you have tried New Life Cycle in Williams Lake. Other than Dave at NLC, or Ebay and being prepared to pay huge shipping, I don't know where you'll find the exhaust pipes you are looking for.
I understand the desire to restore to stock simply because many of our Club members are of that view. However, your exhaust problem is exactly why I never give a fart about replacing stock with aftermarket stuff that may be completely different; it is readily available and usually cheap.
Peace & Grease, Dennis