I just asked Stella to make some Sims which would look like us three, since I'm rubbish at designing things.
It's hard to get a resemblance to a concrete person out of those sliders; they tend to leave the face looking really odd more often than not, but you can see some resemblance. (I'm probably the most easily recognisable, though the fact that I was the one she started with and so she still had more patience probably helped.)
It's a bit depressing to see my paunch on a Sim :)
I intend to make a userpic of my self-Sim at some point, to use for Sims-related entries. (Don't hold your breath, though.)