Picker (drop-down menu) for Global Categories

Hi,

I have enabled the mp-storepicker from the header to display a drop-down menu for all of the stores in my multi-site. I'd like to do the same for listing global categories - Is it possible to do so?

I've seen that you can include a global category list in the sidebar (as a list not a picker), however this isn't the functionality I want to achieve. I'd prefer it in a drop down menu in the header, like the store picker