It will be near impossible to locate those items, simply because of the rarity of the truck.
But, not totally impossible, here are a few suggestions...
You can always bug Joe and see if he will give you any leads. You can also pick up a Hemmings Motor News at your local news stand, I see some pretty rare stuff in there from time to time. Another option is to find other BJ owners or sellers, and see if they have any leads or contacts. E-bay is also a good spot, but I personally have seen very little on there as far as BJ parts go.
Good luck on your quest, keep us posted.
Welcome to the board!