I just recently assembled all of the parts I needed to try and finish a Hawken half stock someone started to build over a decade ago.
I had to get these sundry missing parts from a private seller here and at least three or four different vendors as no single one of them had every thing I needed. This was just basic stuff including an iron nose cap, half stock barrel tenons, an iron pine apple style patch box, sights and ram rod thimbles. The prices quickly added up and of course shipping just added to that. I don't think I'd want to try that again as it sure seemed like a mad scramble to get what few parts were left out there.
Maybe Pecatonica could set you up with everything needed right off the bat, lock stock and barrel? Though your size options may be limited and wait times might be long as mentioned above. I would definitely start there. My hang up was only certain size castings of stuff like nose caps seemed to be currently available even from the folks there. Of course I needed the sizes or style most of them didn't have. When I had everything rounded up I had checked about every vendor I could think of only to find most of them no longer had what I needed in stock and didn't know when they'd get more. As I recall I placed actual orders to Upper Missouri River Trading co, Track of the Wolf, Jedidiah Starr, and a private party to get what little bit I needed. I may have forgotten one or two more? I could have made do and cobbled my own stuff and just poured the nose cap, but I had it in my head that i needed "proper" Hawken parts like all the famous old Hawken rifles had. What an adventure.
Tim A.
PS. if you don't already have it I'd also consider getting a copy of Bob Woodfills' book on Hawken Rifles too. Its available through the NMLRA.