The Illusive Obr.43 Shoulderboards...
These are a real pain in the neck to track down on the English language part of the web, after a long old trawl I managed to find a few dependable vendors:
above links for infantry shoulderboards specifically but both vendors carry a great variety, might be worth grabbing a number of items to make the shipping from Russia cost effective.
I've fired a bullet on every continent. Nearly hit someone, too.
If anyone is worried about ordering from Russia, I can confirm that Schuster are very reliable, and as BF mentioned, they have loads of stuff which is sometimes difficult to get here in the UK.