I have had the same issue with displays at our Living History Events. I was able to purchase fake barb wire from a Halloween (That is a holiday where us Yanks dress up as Monsters and look for Candy...much like everyday life) supply house. It was very inexpensive at $4 USD for 20 feet.
It consists of a semi-hardened string painted a rust color with silver streaks. Again this looks real from 1 meter. I don't have any real good pictures of it but you can see it here in front of an M-20.
It passes the 1 meter test in appearance. Many have come up to warn us about using real barb wire only to find that it is fake. It is much more plyable than wire so it can be formed easily around objects. But most of all it is safe for the public
I highly recommend it. Don't have the URL right here. I will post a reply with it within 24 hours.