In addition to being a big anime fan, I also was a big comic book fan in my youth. I recently came across a trailer for The Dark Knight Returns Part 2, an animated film based on the famous 1980s comic book. After watching it, I felt it would mash-up pretty well with Madoka Magica... with Homura being Batman, of course!
Enjoy The Dark Homu Returns!
Just to be clear...
Homura as Batman
Madoka as Robin
Sayaka as Superman
Mami as Commissioner Yindel
Kyouko as Jim Gordon
Kyubey as The Joker