Officially, you can't, and I'm not sure why you would want to either.
If you're dead set on it though, you can remove it altogether, by editing the skin file associated with it.
Download the attached archive and extract the folder it contains into your "MC Installation directory\Skins\Standard View Skins" folder.
Then, having done that, change your skin to "PixOS (No Status Bar)"
This might not be what you want, but it's as close as you can get, and will only be missing in that one, single skin choice.
-marko