Good luck, Jim...Really!!
It's hard enough finding a collector who has one in his personal collection much less one who has a dup. I don't have them myself.
I don't think it's so much we SS'ers are cheap...or are we? Is it mere coincidence the two high-end items missing are Silver Strikes?
Maybe someone can put a "charity bowl" at the entrance to this weeks affair, so people can donate funds toward the purchase of the missing items?