you know, i always think that mugen need more zombie inspired stages, also here is some ideas for some marvel zombies stages, i would try to make these but im really had no clue about how to do stages.
magneto last stand, stage inspired after the magneto vs zombies fight.
-the city ruined and destoyed, with the magneto helmet on the ground shinning along with his cape over a light post.
-the floor of the stage start to collapse and the fight goes on in the sewer.
it would be something like this but with the suggested ideas.
ps:interesting topic, i will be posting more ideas, and also i agree with borewood about a mmv stage.