Exit Pop-Up Coupon

I've been searching to find an extension that has Exit Coupon.

Such as when a customer enters the website; they go to leave the extension/plugin will pop up giving the customer a discount coupon code to use toward their purchase; end result; saving the sale...

Ive seen others post on this but it seems no one has created anything like this? or i just cant find anything? would anyone be willing to create it? Offer it for sale in Extensions i would gladly buy it.

I also looked for something similar, you should check out http://zoomanalytics.co
The campaigns feature is exactly what you're looking for