Check out Hunter Rosenberg’s Gumroad page. He offers 3D stock and an insane amount of photographs for 3D artists and concept artist.
Before I bought the 2 DARPA robotic challenge packs, I personally checked back with him on facebook and asked if it’s cool to use the images for photobashing. He confirmed. You buy the pack, you use the images and done.
This is a godsend for an artists like me. I struggle with hard surface drawing – I’m just to impatient – but the two packs give me plenty of robotic limbs, joints, shells, electronics, hydraulics, sensors and whatnot to use for my designs and it could not be more helpful.
Check it out and also browse his other product here: https://gumroad.com/will_grello