If your heart is really set on one, post up on duckboats classifieds, or write/call/email the Duck Commander factory. If they don't make them anymore, I'm sure they'll direct you to the call currently in their line that is the best replacement for that call.
The more important question you gotta ask is, "If that model of Duck Commander really was so great, why aren't they makin' it anymore?" Why would any call maker, who made a call that made sounds so perfect the FBI checked it out and was able to market it (for profit) at under $20, stop making that call? And why would hunters allow them to drop that call line? I'm just sayin'.......that line of thought isn't logical, even for southern rednecks, or should I say especially for southern rednecks.
But I am sure that if you are willing to pay a good price for a cutdown duck commander, you will be able to find someone with one who is willing to part with their personal heirloom.... Maybe Si?