Well, I'm not sure how to approach helping. I'm not sure where you could get such a thing as there isn't much of a call for it (as I know). If you are just wanting to practice (and aren't trying to find something to paint up and sell), you could frequent places where they are doing Work In Progress and pull the images down to your PC. But these wouldn't be legal to sell nor post as yours (though you painted on them). Otherwise, it might be a case of asking for some Poser people to throw a few quick renders your way. Maybe someone else has some ideas.