DrawMohammed.com has dozens of outrageous Mohammed parodies.

Muhammad-cartoon.com also features an extensive compilation of extreme parodies.

Retecool's Mohammed Photoshop contest (though not all the entries use actual depictions of Mohammed).

The Infidel Bloggers Alliance Mohammed Cartoon Contest

Reporter: "This Islamic scholar says the crucial injunction in the Koran is against mocking the Prophet, or other authorities."
Sheikh Haitham al-Haddad: "It's totally prohibited to do something that belittle the prophets of Allah, and depiction is part of belittling the prophets of Allah, from one['s] anger.
[Printed-out pages of the Mohammed Image Archive shown being placed on a table.]
Reporter: "Traditionally, Islam has frowned on any representations of living beings. But painters in Islamic countries have depicted Mohammed for centuries."
[Close-up of this image from above showing a medieval Islamic depiction of Mohammed.]
Reporter: "Despite official disapproval, portraits of the Prophet are sold to devout Muslims in Iran today."
[Close-up of this image from above showing Iranian portrait.]
Sheikh Haitham al-Haddad: "Some people have a Muslim name, and they claim that, oh, they might have Muslim parents, but they have left Islam totally."
Reporter: "But [gesturing toward Mohammed Image Archive pages] these are from, these are from medieval Persia, from the medieval Ottoman Empire, so surely they're Muslims."
Sheikh Haitham al-Haddad: "No, not necessarily. Islam is a practice. It is not just a claim. Islam is a way of life. So, we practice Islam in our daily life in every inch and each aspect. It's not just a claim and then we can do whatever we want. No."
Reporter: "So [pointing to Mohammed Image Archive pages] these pictures were wrong."
Sheikh Haitham al-Haddad: "Of course. Hundred percent wrong."