In exploring the new wp_page_menu() function, I realized that there is a byproduct of wp_list_pages that is unintuitive and possibly problematic for people wanting to output a menu. The 'include' argument overrides the use of child_of, parent, meta_key and meta_values parameters.
Menu creation assumes that only some top level pages will need to be used, thus the need for 'include', but wp_list_pages assumes that if you're including only a subset of pages, you're not including the subpages as well. Makes sense on both accounts.
For menu authors, I think expected behavior is that a top level menu would include subpages as well (e.g. a rollover horizontal nav).
I'm submitting a patch that delivers that expected behavior to only the new wp_page_menu() template tag. It reverse engineers the include by using the 'exclude' argument to exclude all pages except the ones passed with the wp_page_menu 'include' argument.
