Is it possible to create more than one design in a WordPress theme? [closed]

It is definitely possibly to create 3 (or more!) layouts within a WordPress theme. It all depends on your skill level and comfort with PHP and WordPress if you can do it yourself.

WordPress allows for creation of multiple page templates within your theme (http://codex.wordpress.org/Page_Templates#Creating_a_Page_Template).

WordPress also allows for creation of multiple menu location with menus attached to them: http://codex.wordpress.org/Navigation_Menus

Each page template could have a different menu linked and different designs.

You could use a theme framework like Thesis or Thematic which allows for this sort of creation within the theme framework itself.

You could also find a theme that has layouts which resemble yours already and work within that theme. You can add additional menu locations like this:

register_nav_menus( array(
    'new_location_1' => 'Custom Menu 1',
    'new_location_2' => 'Custom Menu 2'
) );

And you can then swap out the menus on particular pages like this:

function modify_nav_menu_args( $args ) {
    //Check if we're on correct default menu location
   if( 'header_navigation' == $args['theme_location'] ) {
        global $post;
        //Check specific post ID to replace menu for
        if ($post->ID == 2)
            $args['theme_location'] = 'main_navigation';
    }

    return $args;
}
add_filter( 'wp_nav_menu_args', 'modify_nav_menu_args' );

Also, as long as your theme is using the body_class function, you can do a lot of restyling by using the classes that get added through that function.

So, yes, it is possible.