After chatting with the nice people at Uri-review, I’ve accepted their suggestion that nym, or something like it, would be better constructed more along the lines of a filetype, or even an end-to-end cryptosystem application, than a URI. Thus, I’ve started chatting with the nice people at vcarddav, pkix, and apps-discuss about just that. Specifically, by creating a “signed vCard” extension to the existing vCard standard; and working out an easy-to-use-as-possible set of ways to use such cards.
The name ‘nym’ seems to have been lost entirely in the transition. (Unless it turns out a name is needed for the whole system, but that’s speculative.)