Batman : Dead End
don't get your hopes up to high. it's not a movie but a fan film that this director created to be his calling card so to speak. this is the same guy who directed Insomnia.
it's hard to believe that "Boner" from the TV series "Growing Pains" plays the joker in this. this is the best portrayal and most accurate version to the joker i have yet to witness.
for more detailed info check out -
Making of Batman : Dead End