This is an old idea, but many surgeons don't perform it anymore because once you move fat from one area of the body and put it in another two things tend to happen: the fat is just re-absorbed into the body so the results don't last long, and/or the transplanted fat tends to harden and make things like cancer detection via mammogram very difficult.
Stem cell is an intriguing idea, but not much experimentation done on it right now.