Check with a masonry supply distributer. They use a mesh similar to that (well, it's criss-crossed, not holes) in between layers of block to increase the strength of the wall.
As for size, I know that at work we have a roll of it, about 2.5'-3' wide, probably about 30'-40' long. I don't know why we have so much... the owner was only planning on having a 20' long wall built, but if he finds a bargain he buys it all.