The Rifle Shoppe is the only place I know of that makes a complete parts set for the 1817. Years ago they used to offer completed guns but they are so inundated with orders apparently they do not offer that option now. Track of the Wolf has offered 1817's for sale once in a blue moon over the years, but it is very rare. They used of carry parts from The Rifle Shoppe but only have a few parts left now. I bought parts from Track years ago (it was a very trying experience) & from the The Rifle Shoppe (bought a 1817 lock set from them) which went okay.
I eventually finished the rifle while taking a machining course at a junior college. I wound up machining every screw on the gun including the wood screws, lock screws and breech plug & made the ramrod because Track sent me a 33" rod instead of the correct 36" one. Had to weld up casting flaws also - good times!?
Here's a couple of photos of mine from 2007:
good luck with your search, Mike