How can you have more power than a SA? As far as I'm aware, the only thing a SA can't do is use a few of the more obscure console commands. They can change all RTB settings (with given permission), and that's pretty much all a server host can do after the server is set up.
Alternatively, you could make your trusted friend become part of your family, live in your house, and hence be able to use your BLID, and therefore have two instances on the same hosted server. Both would have host status because it's the host BLID.
Of course, that last thing is a silly idea :)