Its been a long time for me too...Back in '1980, I Worked with a guy who started on one but never finished, so he sold me what he had... a tiger maple stock roughed out, a blank .54 cal GR Douglas barrel, set triggers...lock plate assembly, various odds N ends... ...percussion...Back then we didnt have no internet or youtube vids, all I was going off of was a general idea and the Foxfire book....I didnt know what I was doing, I was just a kid out of Highschool...
I made the rear site out of a RR spike, front site was out of a silver dime...also cut a new sideplate for the lock mechanism out of a piece of flat stock...Now, this was all by hand, hacksaw, files, handdrill and taps, rasps, woodworking carving knives and chisels etc...I do remember working on that curly maple stock was a real B on account of no straight grain!...
I somehow managed to get it all put together, and thanks to a quality barrel, it was one dead on accurate rig! Carved a charging buffalo in the stock even...Pawned it off for $250 in Rapid City SD when we needed some money...I still have some left over parts around here!...
So I think theres probably still a place where you can buy all the components and do it yourself? This way, you can choose the grade of the stock and components and build your own personal rig thats not from a Kit?
Best yet is if you can find an old guy in your AO that is into flintlock building and go spend some time in his shop! You know he's got everything you need and would probably enjoy showing you what he has learned...
Some guys are extremely talented with metal, others with wood...a gunsmith has to be good working with both...thats the art and challenge!...Good on ya!