How to create custom 403 page for a particular content type?
Try looking at the Custom 403 module, or the Teaser 403 module .


  Custom 403
  
  This module provides helpful messages to users when they encounter a 403 (Access Denied) page. Depending on different role(s) permissions set on the specific node or content type, the administrator can specify messages accordingly. The user who encounters the 403 will obtain more specific information on how to obtain the role(s) required to access the node.





  Teaser 403
  
  This module is designed to expose teaser content for sites which normally require users to login to view nodes.