How to require registration during node creation...

I've done a fair amount of searching, and not found a current contrib module or workaround that would allow for this situation. I currently need the following functionality on two separate sites.

I need to allow an anonymous user to access a node creation form that is only allowed for "authenticated users", BUT present them with a registration form at the top of that node creation form if they are anonymous.

I can envision an AJAX way of doing it to simply include the form at the top, and when the main form is created, submit and validate the registration form first, then retrieve the user data to submit with the new node creation form. However, that doesn't solve the issue of presenting the full node form to an anon user prior to being an "authenticated user".

Does anyone have any knowledge on a decent way to accomplish this?? Any help or direction pointing would be greatly appreciated.