Love the colors and the look on Harley Quinn's face is priceless!

It would be an interesting thing to see her truly intergrated into a film full on and stuff(I think she was in Birds of Prey, we all know that show kept going...) and even into the current Nolan-verse given its dark nature and presentation. Might make for a clever break from the darkness and truly give the "Dark Knight" someone that is whimsical yet committed(in both sense's of the word) as a character. A nice twist might be a devlopment from a truely deranged Batman Imitator(think a crude "Batgirl"), to a "Normal" life and job, to the Joker's playful sweet thing with a mean right hook and a rubber chicken with a brick stuffed in it. Say over the course of 17("Bat"Girl) till 27(Harley Quinn) with 22 till 27 being her "normal" time. Throw in hard times(in this Gotham who isn't having hard times) and maybe a chance meeting(with her "puddion") and take it from there. Haven't seen Dark Knight yet and will most likely have to wait for it on DVD(missed it at the local theater), but maybe this idea would make a good 4th installment instead of a 3rd movie. I might be a chilling tale of someone that was sort of on Batman's side and was in some ways just like him:

-First take on such a responsibility so young and do without all his 7+ years of training to do so well almost gaining his trust and maybe "a spot at his side(?)" .

-Secondly giving it all up, all the issues and duties "like that" with very little reason and returning to a "Normal" everyday life.

To...

-Thirdly going too far and becoming that which she once fraught if not worse with little or no reason again. Furthermore doing so willingly with his great rivial(The Joker). Making her a sort of Microcosm of his life maybe?