Christopher Nolan is doing some interesting work on the character of Two-Face in the upcoming Dark Knight film. The character is being shot twice, with actor Aaron Eckhart both in and out of make-up, and playing the character differently, so that you have a good idea that Harvey Dent is, in fact, a psychopath with a dual personality.
The good news is that this will likely make it a much more realistic experience than the last time we saw Two-Face onscreen. However, it's an editing and technical nightmare, and it might end up costing a whole lot of money. Still, this project gets better and better all the time.
Dark Horizons.com: Ambitious Two-Face Plans For "Knight"