for a while now i have had no end of trouble in locating grayscale depth maps (3D reliefs) i can find PLENTY for sale but i am a cheapskate and have NO intention of ever paying for the files.
anyway morals and opinions are a CHOICE, that aside why dont we share either pictures or links.
nipic.com = chinese paid for files, great selection but VERY few free
http://333cnc.com/?c=lib&cat=8&lang=ru nice selection of free stl and depth maps
http://vt-tech.eu/articles/cnc/79-artcam-3d-models.html great site with lots of freebies
http://cnc.userforum.ru/viewforum.php?id=8 another great site with loads of BOTH paid and free stuff
http://www.cnczone.com/forums/news-announcements/60100-free-stl-models.html more free stuff