@ragamuffin: Thanks! All of my iinitial ideas were very similar to what other people had made for the challenge. So instead of doing something that had already been done by someone else, but do it worse, I did tried to make something a bit different.
Here's my attempt at doing more realistic rendering. As you can see, I failed with the likeness of the person, but I think that the rendering itself doesn't look too bad.
Also here's also another sketch