As per a suggestion by AngryBeth Shortbread, I have this morning been playing with an Engine-driven system that attempts to match one's features to the most appropriate star of stage or cinematograph. I have to say that I am not entirely convinced by the results; repeated use with various pictures resulted in the following being judged most similar and appearing most often, the more common on the left:
I must say that one thing that I have never been told in Second Life is that I look like Christina Ricci, and I think it unlikely that I ever will. Still. Diverting.