Actually the vast majority of what you're seeing here began as shapes in illustrator and then painted & textured in photoshop. I suppose the photos I took of rust and used as texturing could count as "stock," though. I dunno...does that count?
hmm well, as I said, the art is very well done.. What i can guess are the signs in the central building, which seem to be shading off, which happens when blending in stocks I also think the building on the lower right corner with the lights, and the edges of the buildings near the 'camera'... I could be wrong though, the stocks are too well blended