There are two main ones: Brian Asbury from Acton Ontario, Canada, and Dirk Leegwater (LWD) in Holland.
http://www.lwdparts.com/
Brian does not have an online store, but he can be reached on this forum under BCA and can email a parts list.
As well, John Bizal from midwest Military makes some repro sheet metal parts.
https://midwestmilitary.com//midwest...encarrier.html
None of these will be your one-stop shopping link though. Between the three of those, and the occasional reproductions or finds made available on this forum, we all manage.