Allows you to use a page as a custom post type archive (similar to the "posts page" within reading settings)

class-nh-post-type-pages.php

<?php
class NH_Post_Type_Pages {

    private $pfpt, $post_types;

    function __construct() {
        $this->get_post_type_pages();
        add_action( 'admin_init', array(&$this, 'reading_settings_section') );
        if(!is_admin() || (defined('DOING_AJAX') && DOING_AJAX)):
            add_filter( 'pre_option_show_on_front', array(&$this, 'filter_show_on_front'));
            add_filter( 'pre_option_page_for_posts', array(&$this, 'filter_page_for_posts'));
        endif;
    }


    public function filter_page_for_posts($option) {

        $qo = get_queried_object();

        if( !is_null($qo) && in_array($qo->ID, (array) $this->pfpt) ):

            global $wp_query;
            $post_type = array_search($qo->ID, $this->pfpt);
            $wp_query->set( 'post_type', $post_type );
            query_posts(array(
                'p'         => $qo->ID,
                'post_type' => 'page'
            ));
            add_action('loop_start', 'wp_reset_query');
            return $qo->ID;
            endif;
        return $option;
    }

    public function filter_show_on_front($option) {
        $qo = get_queried_object();
            if(!is_null($qo)) $option = 'page';
        return $option;
    }

    public function reading_settings_section() {
        add_settings_section( 'post_type_pages', 'Post Type Pages', null, 'reading' );
        register_setting( 'reading', 'nh_post_type_pages', $this->sanitize_custom_post_type_pages);
        $this->custom_post_types();
        $this->settings_fields();
    }



    private function settings_fields() {
        foreach($this->post_types as $post_type):
            add_settings_field(
                "{$post_type->name}_page",
                $post_type->label,
                'wp_dropdown_pages',
                'reading',
                'post_type_pages',
                array(
                    'name'              => "nh_post_type_pages[{$post_type->name}]",
                    'show_option_none'  => __( '&mdash; Select &mdash;' ),
                    'option_none_value' => '0',
                    'selected'          => $this->pfpt[$post_type->name]
                )
            );
        endforeach;
    }
    private function sanitize_custom_post_type_pages($input) {
        die('test');
        return array_filter($input, 'ctype_digit');
    }

    private function custom_post_types() {
        $this->post_types = get_post_types(array(
            'show_ui'  => true,
            'public'   => true,
            '_builtin' => false
        ), 'objects');
    }


    public function get_post_type_pages() {
        if(is_null($this->pfpt)):
            $this->pfpt = get_option('nh_post_type_pages');
        endif;
        return $this->pfpt;
    }
}
$nh_pfpt = new NH_Post_Type_Pages();

Todo

• Add admin settings page
• make function work for dynamically set page id
• Figure out template hierarchy
• Add code commenting