After the initial outrage at the killing of the cartoonists in France, I started re-assessing my attitude to Charlie Hebdo and found myself thinking that it is a very offensive publication. Obviously I don't condone the use of murder to silence the magazine, but it is true that here in Israel many of its cartoons would be deemed racist and banned from publication.
There are plenty of depictions of Mohammed around if you choose to actually look for them. Take this compilation of Renaissance depictions of Mohammed: http://www.zombietime.com/mohammed_image_archive/euro_medi_ren/. Apparently Moslems also depicted Mohammed: http://www.zombietime.com/mohammed_image_archive/islamic_mo_full/.
The murder of the cartoonists raises another issue: the status of Mohammed in Islam. Basically, Christians think that Jesus is part God, while Moslems assign a semi-divine status to Mohammed in which he remains human but apparently is so sacred that we mustn't even imagine what he looked like. And Jews? We barely mention Moses. The Passover Haggadah, which is all about the Exodus completely ignores him. You might say that we are quite happy to insult his memory. On that grounds at least Jews must count as better monotheists then Moslems and Christians: No one over-shadows God. Though, of course, each religion has its own oddities. Jews ascribe magical sacred status to a building (the Temple).
If you object to depictions of Mohammed, its a bit odd to ignore depictions of God. Christians depict God all the time. The attitude would seem to suggest that Mohammed was more important than God, though it may be related to different ideas of the nature of God - Moslems are less likely to "humanize" God.
As for creating images of Mohammed, both orthodox Jews and Moslems make a big fuss about having no images while printing plenty of images of rabbis and imams. It seems to me that there is an element of idolatry in hanging up giant pictures of Khomeini or Rabbi Ovadiah, though perhaps it's better that religious zealots allow pictures if the alternative is that they allow none.