Zazzle

Zazzle is a retail platform for consumers and major brands, offering billions of retail quality, one-of-a-kind products, created on-demand and shipped within 24 hours. This process is made possible due to years of R&D, proprietary manufacturing systems, and hard core software development. According to the company's website, each product they ship is made - literally - one at a time, right after ordering. They'll even let you "design your own".