Looks like this place is more for industrial and heavy equipment but I did see some light trucks listed like this Silverado. They have listings all over the country.
Doesn't look like you have to be a dealer either.
2014 Chevrolet Silverado 1500 4x2 Regular Cab Pickup
4.3 L V6 Gasoline Engine, 2014 US EPA Label, Automatic Transmission, Air Conditioner, Spray-On Bed Liner, P255/70R17 Tires, 8 ft Bed
www.ironplanet.com
Doesn't look like you have to be a dealer either.