[aussiblue]

A good brake shop could cut the line at the leak point fit a hard line compression joiner and a make a new hard line back to the rear T junction or to any other nearest existing joint/junction or brake piston. However, due to liability concerns, most would likely prefer to fit a new OEM line. There are also likely to be RWC failure issues with any patch job like the one you suggested. At best it's a high risk temporary measure so you can drive slowly and very cautiously to a brake shop.