Selenium WebDriver won't let you add/change request headers

Selenium looks like being a good tool for writing some automated browser tests. Selenium WebDriver with the python bindings looks like it could be fantastic for doing this. But then they go and spoil it… I need to be able to modify the headers in my requests as part of my tests. WebDriver doesn’t let you do that. Worse, its a conscious design choice they have made to not let you do this since they want WD to only do what a user can do.