I think the OP is looking for pics of TRUCK CAMPERS
May I suggest RV Trader and RVT and set the search engine to truck campers. lots of pics there.
I hate to sound pessimistic but the truck camper folks don't follow the regular RV forums like others do. There are two truck camper resources worth looking at and that is Truck Camper Magazine and Truck Camper Adventure which is more of the hardcore offroad and oddball stuff but still worth looking at.