Had this in mind and been searching around the forum past a longtime but my bad i end up nothing good.
Not sure if this is possible but this is what i was searching around :
1. User click " Go to App" authorising basic info + email + phone number
2. User details are already pre-populated on the next page that loads such as name , email and number etc ( Facebook Application Page )
3. User click Submit button on the page to get the account created for him in the interface.
If you have API key provided by the advertiser , how would you use it with this method???
Any thoughts are greatly appreciated.
Mehdi
I am working on doing this with a viral app, except, im starting the path after confirmation email. Apparently FB doesnt like co reg directly after the app has done its job. Not gonna risk my account.
i have no idea about bann hammer of FB but i would like to test it on a clean new account. Also , I dont think facebook will be able to see you are doing coreg with this method. PM me i will tell you how... 
Mehdi