Create a search of some kind for Tropicana chips on ebay and run it from time to time. I'm not sure how you would specify the kind of mold in a search though as many sellers don't know or don't care. You could try adding "King" to the search for Tropicana and at least catch those who do include it in the description. You would miss all the other auction lots, though. Putting "first issue" in the search might also work.

Asking for them on this bulletin board (as you did) is certainly a likely method of finding some.