The Longboard Collectors Club has this meet several times a year at various locations. This Saturday it is in Malibu Beach at Topanga Ranch Motel from around dawn to late afternoon.
Vinny, the vintage boards at this meet are kinda pricey$$$ for what you're looking for. Garage sales would be best bet and usually can find old board for less than $200. I'll keep an eye out for one for you.