This is definitely a task that requires calling in some favors.
Order pizza, make a few dozen cookies or a giant cake for all your family and friends that you're going to need to help you complete the penny project.
The final product will definitely give you a unique color hue, texture and something to talk about. Wether you've glued them onto a floor, or stuck them in cement and covered them in lacquer for a backsplash, the look will be worth the effort.
The old adage "see a penny, pick it up..." may not be as easy once you're done here.