A small suggestion if you don't mind, for the ad position and all that, why don't you have it in the skin colors, etc? because certain skins may need the ad banner below the welcome table, some need it at the top.
Like the vF website skin, that needs it below the welcome table as it will mess up the skin. But what if you have a skin like that on another forum, but you want to have the ad banners above the welcome table on the certain skin, and it just messed up your whole plan. I just thought of this, because on a forum I am fixing up, I wanted the ad banner above the welcome table, but just remembered if I do that, the other skins will mess up.
