Check out car-part.com
can search a lot of yards / recyclers.
May have to search a different term like 'fender' or something. Sometimes they have full images of the salvaged trucks for you to see. If you see them being in ok shape in the images, just call the yards and ask...some dont keep the whole truck around very long.
Also, if you havent...make sure the Whackers have not worn a line clean through the paint to the metal below...sometimes happens with those. The OEM white paint is also single stage, so it may wear down a little quicker than clear coat.