Do they have to be silver, or will gold work? And if gold were acceptable, I guess you also have also checked with RAM Electronics? (I guess my Google is no better than yours!)
Sorry, I just figured small things like banana plugs would be directly stocked by the vendor. BTW, out of curiosity, what is the amp with "peculiar" speaker posts where BFAs won't work?
Anyway, good luck in your search.
Steve