Multiple sub directories for theme template pages

When I want to change a specific part of template, such as header OR footer then I use conditions like this –

if(is_404()) {
    get_header(`error`);    //loads header-error.php
} else {
    get_header();           //loads header.php
}

In your case, you want to load a completely different template, Now the only action hook I can imagine is – template_redirect, Which can be used to tell wordpress to load a different template as per conditions.

Example –

function wpse62337_zurbified() {
    if ( CONDITION ) {
        include (TEMPLATEPATH . '/zurb/page.php');
        exit;
    }
}
 
add_action('template_redirect', 'wpse62337_zurbified');