I know of this company in the UK who, when supplied with a photo, will caricature the subject and then print it onto icing. They also give provide a hard copy of the image which you can have to keep long after the cake has been eaten and enjoyed.
The client in this instance was a huge James Bond fan. He was delighted with the cake so all went well. The cake itself was a 10" zesty lemon, triple layered with lemon buttercream and lemoncurd.