Referencing other nodes created by the same author
some time ago, I created something similar. A drop down box (client profile) for the current user only - i.e. when creating a content type, the user would be able to choose a client profile, but only from a list of client profiles THEY authored.  

I accomplished this using the following:


using a custom Node Reference Module, I created a field on the content type that used the node reference as a drop down box
added the following to the .module file, around line 878:

global $user;

if($user->uid != '1') $query->condition('n.uid', $user->uid, '=');


This creates a condition on the sql query that if the user isn't 1 (admin) it references the user id of the node creator, relative to the current logged in user, while Admin can override

If you going to go with this approach, be sure to rename the files and module into a CUSTOM module (I renamed mine custom_node_reference for simplicity).