Copper/Nickel is used extensively in the UK and is fitted by Rolls Royce, Aston Martin and several others. Trade name is Kunifer.
Bundy tube - Wikipedia, the free encyclopedia
If not properly attached at regular intervals any pipe is likely to eventually fracture (especially on corrugated roads). Pure copper would be prone to work hardening & cracking. Interesting to read in the Wikipedia article that Kunifer is more rigid than Bundy tubing and expands less under pressure.
As Arthur mentioned, check with your local transport authority. One problem I forsee is it might be the correct alloy but it looks like copper so how do you prove it to the testing authority ?
As there aren't the same corrosion issues in Australia (they put Rock Salt on UK roads during winter to melt ice) then the readily available plated steel brake lines would be OK.
Some more reading here
Copper.org: Applications: Automotive - Copper-Nickel Automotive Vehicle Brake Tubing
If you source a double flaring tool, some tube nuts & flare nuts and the correct tubing it's quite easy to make your own pipes.
Colin