Codeko

With this plugin you can set any post type (or posts types) as parent of any post type.
Urls will be wellformed, redirects will work, breadcrumbs will work fine.
This plugin is recomended when you need a url structure with a mix of post types. Any url structure you can imagine could be done.
Post types rewrite slugs will be ignored

Custom Posts Parents

Set any post type (or types) as parent of any post type. Any post structure can be created with this plugin.

BeardedGinger

Designed to display the Parent, Child, and Grandchild hierarchy in the most straightforward way out of the box.
This plugin will provide a widget that locks the Parent page as the widget title.
If this is a child of the top parent, the widget will display the Parent as the title of the widget and a ul of links for all siblings of the current page.
If this is a grandchild of the top parent, the Widget will display the same as the scenario above with the addition of a sub ul of all siblings of this grandchild.
Test it out, if it doesn’t work like you want out of the box, this plugin isn’t for you.

Simple Page Hierarchy Widget

Displays the most logical arrangement of Parent, Child, & Grandchild pages.

Custom Posts Parents vs Simple Page Hierarchy Widget