Guns shows are not your friends unless you are looking for the esoteric or very specialized. Getting to know your local gun dealer is the best bet.
Case in point, I befriended a local dealer when he had troubles with the Local DA trying to make a name for herself and a pathway to the House of Representatives. Said dealer came upon an estate consignment. I got a phone call about a Colt Python at a price I could not turn down. Enough said. I love my one of the last out the door of the factory Pythons that did not cost my my left nut.