That Gaming Site looks into Trophy levels:
This is a question that has fluttered around the web a few times. What is the real use for the trophy level system?
We believe that this will play a large part in Home. If you think about it Trophies was first revealed as a Home addition. Remember them 3D trophies, the ones you could show of in your own trophy room? This brings me to think that the level up system would be linked with Home also. I believe Sony always planned to release 2D trophies from the beginning and not just as to side track us from the real goods.