Index: src/wp-admin/network/site-new.php
===================================================================
--- src/wp-admin/network/site-new.php	(revision 35702)
+++ src/wp-admin/network/site-new.php	(working copy)
@@ -110,10 +110,26 @@
 		do_action( 'network_site_new_created_user', $user_id );
 	}
 
+	/**
+	 * Filter metadata passed to wpmu_create_blog in Add New Site Admin Network Screen
+	 *
+	 * @since
+	 *
+	 * @param array $meta List of meta for the new blog.
+	 * @param string $newdomain Domain of the new blog.
+	 * @param string $path Path of the new blog.
+	 * @param string $title Title of the new blog.
+	 * @param int $user_id ID of the new blog administrator.
+	 * @param int $current_site->id ID of the current Network.
+	 */
+	$meta = apply_filters( 'network_site_new_blog_meta', $meta, $newdomain, $path, $title, $user_id, $current_site->id );
+
 	$wpdb->hide_errors();
 	$id = wpmu_create_blog( $newdomain, $path, $title, $user_id, $meta, $current_site->id );
 	$wpdb->show_errors();
 	if ( ! is_wp_error( $id ) ) {
+
+
 		if ( ! is_super_admin( $user_id ) && !get_user_option( 'primary_blog', $user_id ) ) {
 			update_user_option( $user_id, 'primary_blog', $id, true );
 		}
@@ -219,7 +235,21 @@
 		<tr class="form-field">
 			<td colspan="2"><?php _e( 'A new user will be created if the above email address is not in the database.' ) ?><br /><?php _e( 'The username and password will be mailed to this email address.' ) ?></td>
 		</tr>
+
 	</table>
+
+	<?php
+		/**
+		 * Fires after the Add New Site Admin Network Screen Form is rendered
+		 * and before submit button is displayed and form tag is closed.
+		 *
+		 * Add you own custom fields here when creating new blogs in a network
+		 *
+		 * @since
+		 */
+		do_action( 'network_after_site_new_form' );
+	?>
+
 	<?php submit_button( __('Add Site'), 'primary', 'add-site' ); ?>
 	</form>
 </div>