I just re-plumbed my AD truck with Fedhill Cunifer alloy lines. They are DOT approved, will not rust, and the flares come out perfect every time, plus you can bend them with your bare hands. Tom at Fedhill is enormously helpful and will loan you (for $25 to cover round trip shipping) a professional flaring tool for 2 weekends, which comes with a tubing cutter, file and even a roll of solder for mocking up your lines, when you buy lines from him.
www.fedhillusa.com
The only thing that leaked in the whole job was the residual valves - used the aluminum ones, then found a million threads here, on the HAMB and on Stovebolt directing me to use the brass ones from ECI. They are on order.