As much as I absolutely love, love, love Arkham Horror, the only thing I feel that is truly missing from the game is the ability to fight Heralds other than The Dunwich Horror. The Dunwich Horror wasn't originally a Herald when it came out, but I know that was changed with Miskatonic.
Heralds obviously impact the gameplay significantly and make the game much harder for the investigators. How cool would it be to have a token for each Herald that is placed at a specific location on the board at the beginning of the game? The investigators could make an attempt to kill the Herald in order to eliminate those particular negative effects and get an awesome reward for doing so, such as receiving an item of their choosing or maybe removing a doom token from the doom track.
Are there any fan made rules or mechanics out there that introduce this idea and allow for Heralds to be fought as a sort of mini-boss fight like Dunwich?