Decide what kind of brake lines you want (2 line or 3 line), buy some plastic aquarium tubing or something similar and fake up a set of lones the way you want them routed, measure that all up and call http://www.cyclebrakes.com and have them make you a custom set of Galfers... That's what I did.
BTW, it's a lot simpler of you go with a 3 line setup, because then there's actually only one measurement to make.
If you are happy enough with the quality of the original lines, I would take them to a local shop that makes high pressure and hydraulic lines. There's a very good chance they can just shorten the lines and put new ends on. You might take the whole bike over first, and they can tell you for sure; they might even measure for you too.
Be sure to take into consideration the length needed with the forks fully extended. As with many other things, better to be a little too long, than a little too short... ;D