My dad still talks about his '61 Pontiac all the time. We go to car shows together, him in his '32 3 window coupe & me in my SS, and he keeps a look out for it. I think he would sell my mom for that car, lol! If you are not worried about finding the exact car but one that looks like it, try auto magazines. They have a lot of classics for sale in the back. I would love to buy my dad his Pontiac but he wants THAT car back and no way of finding the vin #. And as far as asking people at shows, tell them the story about your dad, if they arent selling, they may know someone that is.
Good luck! And dont sell the Camaro, sell your stang