Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 12646)
+++ wp-includes/post.php	(working copy)
@@ -19,6 +19,7 @@
 	register_post_type( 'page', array('label' => __('Pages'),'exclude_from_search' => false, '_builtin' => true, '_edit_link' => 'page.php?post=%d', 'capability_type' => 'page', 'hierarchical' => true) );
 	register_post_type( 'attachment', array('label' => __('Media'), 'exclude_from_search' => false, '_builtin' => true, '_edit_link' => 'media.php?attachment_id=%d', 'capability_type' => 'post', 'hierarchical' => false) );
 	register_post_type( 'revision', array('label' => __('Revisions'),'exclude_from_search' => true, '_builtin' => true, '_edit_link' => 'revision.php?revision=%d', 'capability_type' => 'post', 'hierarchical' => false) );
+	add_post_type_support('post', array('thumbnails', 'excerpts', 'trackbacks', 'custom-fields', 'comments') );
 }
 add_action( 'init', 'create_initial_post_types', 0 ); // highest priority
 
@@ -562,6 +563,50 @@
 }
 
 /**
+ * Register support of certain features for a post type.
+ * 
+ * @since 3.0
+ * @param string $post_type The post type for which to add the feature
+ * @param string|array $feature the feature being added, can be an array of feature strings or a single string
+ */
+function add_post_type_support( $post_type, $feature ) {
+	global $_wp_post_type_features;
+
+	$features = array($feature);
+	foreach ($features as $feature) {
+		if ( func_num_args() == 2 )
+			$_wp_post_type_features[$post_type][$feature] = true;
+		else
+			$_wp_post_type_features[$post_type][$feature] = array_slice( func_get_args(), 2 );
+	}
+}
+
+/**
+ * Checks a post type's support for a given feature
+ *
+ * @since 3.0
+ * @param string $post_type The post type being checked
+ * @param string $feature the feature being checked
+ * @return boolean
+ */
+
+function post_type_supports( $post_type, $feature ) {
+	global $_wp_post_type_features;
+
+	if ( !isset( $_wp_post_type_features[$post_type][$feature] ) )
+		return false;
+
+	// If no args passed then no extra checks need be performed
+	if ( func_num_args() <= 2 )
+		return true;
+
+	// @todo Allow pluggable arg checking
+	//$args = array_slice( func_get_args(), 2 );
+
+	return true;
+}
+
+/**
  * Updates the post type for the post ID.
  *
  * The page or post cache will be cleaned for the post ID.
Index: wp-admin/edit-form-advanced.php
===================================================================
--- wp-admin/edit-form-advanced.php	(revision 12646)
+++ wp-admin/edit-form-advanced.php	(working copy)
@@ -101,13 +101,17 @@
 	add_meta_box('categorydiv', __('Categories'), 'post_categories_meta_box', $post_type, 'side', 'core');
 if ( current_theme_supports( 'post-thumbnails', $post_type ) )
 	add_meta_box('postimagediv', __('Post Thumbnail'), 'post_thumbnail_meta_box', $post_type, 'side', 'low');
-add_meta_box('postexcerpt', __('Excerpt'), 'post_excerpt_meta_box', $post_type, 'normal', 'core');
-add_meta_box('trackbacksdiv', __('Send Trackbacks'), 'post_trackback_meta_box', $post_type, 'normal', 'core');
-add_meta_box('postcustom', __('Custom Fields'), 'post_custom_meta_box', $post_type, 'normal', 'core');
+if ( post_type_supports($post_type, 'excerpts') )
+	add_meta_box('postexcerpt', __('Excerpt'), 'post_excerpt_meta_box', $post_type, 'normal', 'core');
+if ( post_type_supports($post_type, 'trackbacks') )
+	add_meta_box('trackbacksdiv', __('Send Trackbacks'), 'post_trackback_meta_box', $post_type, 'normal', 'core');
+if ( post_type_supports($post_type, 'custom-fields') )
+	add_meta_box('postcustom', __('Custom Fields'), 'post_custom_meta_box', $post_type, 'normal', 'core');
 do_action('dbx_post_advanced');
-add_meta_box('commentstatusdiv', __('Discussion'), 'post_comment_status_meta_box', $post_type, 'normal', 'core');
+if ( post_type_supports($post_type, 'comments') )
+	add_meta_box('commentstatusdiv', __('Discussion'), 'post_comment_status_meta_box', $post_type, 'normal', 'core');
 
-if ( 'publish' == $post->post_status || 'private' == $post->post_status )
+if ( ('publish' == $post->post_status || 'private' == $post->post_status) && post_type_supports($post_type, 'comments') )
 	add_meta_box('commentsdiv', __('Comments'), 'post_comment_meta_box', $post_type, 'normal', 'core');
 
 if ( !( 'pending' == $post->post_status && !current_user_can( 'publish_posts' ) ) )