Design a Visual Mock Up

We manage a 45' wide x 25' high digital billboard. We need a visual proposal designed for a potential advertising client. Using photographs we have of our billboard, we want to visually show the client what their logo would look like if they installed "extensions" (three dimensional attachments) on to our metal billboard structure. An example of a 3D Billboard Extension is what Chik-fil-A does with the cows on their billboard advertisements