Gotham City - the third Batman movie?

I was trawling through Google image and came across this mightily impressive fan poster for a potential third Batman movie (not counting the predecessors of the 80's-90's).

Got to say, it looks awesome and had me fooled for a second or two. 'Gotham City' is actually quite a cool title, as well.

It depicts actress Christen Bell (the eponymous heroine of Veronica Mars and Elle in Heroes seasons 2 & 3) in a Harley Quinn costume, evidently styled on the Christopher Nolan world of the Dark Knight.

This is top work. Fan art for sure, but it looks great. How cool would it be to see a poster like this?

I was pretty miffed, after much web speculation and the like, that the character of Harley Quinn didn't feature in the Dark Knight (who waited until the end like me for those last credits to roll, hoping, hoping...). There was much talk about Sarah Jane Dunn (of Hollyoaks fame, rather dubiously/incongruously) but it all amounted to little more than a half audible cameo as Moroni's girlfriend (boo!).

With that disappointment aside, I still hanker for an appearance by Harley (although with Heath Ledger's tragic death, I'm not certain if that's going to happen - you can't have Harley without the Joker, and it'll be a very tough order to replace Heath who was simply excellent in that role). Running down the list of potential Harley Quinns in my head, Britney Murphy's name tends to surface at the top. It must be the big eyes and the slight edginess to her performances that do it for me. Saying that, Christen Bell would be a great choice, and not someone I had considered previously.

Here's hoping that Harley does make an appearance in the next movie. Who can say, though...