Now that I have a custom compound Name field working ( see http://www.gravityhelp.com/forums/topic/compound-custom-field-not-being-saved ), I need to be able to use this information to create a custom option in the Display Name drop down on the Feed Settings page. I've looked at the gform_merge_tags filter, but that seems to apply only to the Form Editor.
I can't see any hooks that would let me modify $display_names in userregistration.php, and furthermore I'm not sure how I would go about having it pull the necessary info from my compound full name field.
Once I get this part sorted, I'm thinking of putting together a little tutorial if there's interest.
Thanks!
-malte