That is quiet ridiculous.
In Firefox, Changing the color of the address bar is a 4 line piece of code in chrome.css , add some more code to have it only change for your specific scam website, put it in a virus in an email, and you're set.
It can't be much more complicated for a virus to change the appropriate code for IE7 also. Especially for a pc that has been opened up with windowshades or similar skinning software.