Bundy tubing I believe was the North American name. Basically it was steel seamless line with a certain amount of copper in it to prevent rusting. It was the standard forever. You can go with stainless, or you can just use today's off the shelf brake line, which meets the newer specifications.
http://en.wikipedia.org/wiki/Bundy_tube
I personally always referred to the brake tube as Bundy tubing, and was surprised the other year when the parts counter guy (an old guy at that) had no idea what I was talking about.