Justin,
Thanks for bringing this to our attention! I just ran a few tests using IE and Firefox and it does look like the latest version of Hotmail does not support image maps.
Unfortunately it appears as though they are blocking the click event, because rollovers for the alt, title, and href remain in tact. Due to the fact that they are doing this via JavaScript and all email scripts are blocked, I can’t really think of a way to hack this. They’ve obviously put some thought into it and they must have a reason for blocking image maps - even though they are supported in every other email client ;/
We have updated our code analysis to reflect this change, we will also be sure to include this in our tips and tricks section.
Thanks again Justin and happy testing.