If you look in IE7's settings, you will see there is a checkbox that says something like "Allow sript to hide statusbar" I do not have IE7 in front of me so I do not know hte exact text. Only way to be able to get around that is if the user has that checkbox unchecked.
I have been getting around annoying sites that want to hide the status bar and other parts of the browser window in Firefox by right-clicking on the link and select "Open in New Tab". I'm guessing that would work in IE7, even without the help of that check box.
Yes, I know that doesn't answer Partha's question directly, except to say that I dislike sites that do that and in my opinion the question should not even arise.