Hi, i also want to use the program to build a little city and to see how the light will look in a room etc, right now though i have two characters standing in a corridor.You should look into Daz Studio(which is free I think) if that's all you need it to do.
Even if you do find a quality model that is rigged, the bare fact that the question is posed says this might be a bit of a complicated approach for just seeing how shadows fall on the human form.