I don't think anyone here is going to be able to help you, at least not without breaking non-disclosure agreements.
For the majority of apps, you have to make do with the 50 promo code limit within iTunes Connect. However, Apple will work with developers and publishers for larger promotions - for example, the free 'App of the Week' in Starbucks, or this IGN promotion you linked to.
There is no way for 'normal' or typical app store developers to get access to this. You need direct access to marketing/app store contacts at Apple, which is normally only available to developers of a certain size. I'm sorry it's not better news for you. If you are a developer of significant size then you should get in touch with Apple directly.