You know, Bruce, I find people use SO MANY different descriptors in trying to identify that "archetypal South African red" aroma, that I bet we're talking about the same thing!
Either way, it's apparently that particularly persistent strain of brett that's behind the aroma. I've read it described very variously - coal dust, rubber (I don't think of it as rubber myself, but more as a sulfury/irony/industrial/factory aroma), bandaid, medicine, cured meat, smoke ... and for me it occasionally even veers into Lapsang Souchong territory.
In any case, I adore the aroma and actively seek out SA reds because I enjoy it, and also to a lesser extent because it's so gauche according to "internationalist" ideals ...