TS,
This is a good source for blanks and inletted blanks..
http://cabincreek.net/revspecs/colonial-virginia-rifle/
I've two nice early colonial flintlocks in .54 that you are invited to inspect/shoot if you'd like.
I also have two large volumes of original early (Colonial period) rifle/smooth rifle works that demonstrate the different period approach to carving and structure you can borrow...great reference if you are looking for a nice period piece.
Getting the appropriate lock and furniture is key with the right kind of patchbox.
I've a sliding wood patchbox that is the F&I to early Colonial period that I like best historically.
BTW, Collerain round cut rifling barrels are the way to go