I just completed five new pen and ink sketches for Boston Comic Con. A couple of them like the Bat-Girl and Robin and the Wonder Woman are retreads from earlier attempts. I thought I did the Wonder Woman (1920's style) better than my earlier effort. The Penguin is actually one I haven't tried yet.
I always liked the character design they did for the Penguin Batman Returns. However, I never cared for the dirty old man persona they gave him.