As of right now, I have solved this by taking code from another theme to do this for me. But that's not a solution for me in the end, because I want this on all my sites and don't want to edit all functions.php and stuff like that.
First off, I do not want any widget for AdSense or adnetworks... I want a clean one where I can manage the ads like I want! But the widget must support big ads in the sidebar...
Does anyone know of something that can match this?