I'll be running the Joker, Harley Quinn and Turk (a gun toting escapee from Blackgate Prison - as featured in the Blackgate Prisoners by Knight Models). You'll notice from the image below that there's absolutely no resemblance between the two...I don't care. He's not from the Batman universe, so he's open to interpretation. For the sake of argument, let's say that I've painted him as he looked before he got put away.
The flip side of this is that you can't use characters which don't have models yet, such as my Firefly. However Knight Models are releasing miniatures at a surprising rate so it's really just a matter of time.
I'll post a write up and review of the game later in the week.