Based on the advice here, that's what I did. I cut out all the bad parts and spliced in new pipe. I got the factory bubble flared pipes and used that to join it in the front, and then did a traditional double flare on the two ends I connected towards the back.

I only hope that the sections of the pipe I didn't replace which were buried up in the back above the gas tank and rear suspension don't rupture. Those will be a real pain to get to.

So far so good though. No leaks. I just need to properly bleed the system. Th e pedal is still a little soft and I fear I may have to take it into a shop to have them put the ABS and DSC into "bleed mode" on their computer. I'm also getting a brake pressure sensor fault, but I hope that's related to the leak, as I just changed that a few months ago.