(The bike is a 1984 Nishiki International, with non-aero Dia-Compe brake levers.)
How/where can I add a cable adjuster for the rear brake? The braze-on is stupidly narrow, and I don't think it even fits a ferrule. Using one of those rear brake hangers that attach to the seat post bolt would probabaly conflict with the braze on (and it would be horribly inelegant!).
Here is a picture:
