Here's what I ended up finding out after starting this thread:
Neither mcminone or SP have these cables anymore. The only vendor option I found for a new cable was to get the Sony brand sent from Japan. Luckily, a very kind member of this board sold me one that had been purchased back when they were still available. (by mcminone, I believe)
If the order is large enough, I got the feeling from the mcminone representative that they could do another production. Apparently, there isn't enough demand for this cable to keep it as a shelf item.