I had my original brake master resleeved in bronze a couple of years ago. It should last til long after I'm gone. The place I got it done, Sierra Specialty, isn't doing it anymore (they've retired), but here are a few places you might try:
http://www.whitepost.com/brake.html
http://www.applehydraulics.com/
http://www.karpspb.com/
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