Re: Branchline Freight Car Ends
If you go to Atlas' website and into their on-line store then run a search for "BL1" you will see that they still have some Branchline parts still available. Didn't see any ends but they have a number of different doors listed.
They don't seem to list these parts through their normal on-line catalog, you have to run a search for them.
Another option is ebay if you don't mind dealing with them. There is a seller that sells undecorated sets that may have what you need. I have bought several of these sets from this seller and they have lots of good useful parts.