Take a look at sites like Zazzle - http://www.zazzle.com/cr/design/pt-mousepad. Business card companies have them too.

You can lay out elements on a screen and upload images to make a custom product.

I am interested in creating an application like this. Is there a way I can do it with relative ease? Will it require thousands of programming hours, or is there an app or prebuilt script out there I can use to create similar applications? I am very interested in doing this.