Getting menu items like get_pages

I need a way to create a custom HTML template for the wp_nav_menu function. I’ve heard of custom walker classes, but these don’t appear to be helpful enough to achieve what I’m trying to do; at least as far as I know because of the lack of documentation towards walker functions. What I need to do is be able to add a ‘hoverable’ class to all top level menu items. I only need the menu to go two levels; top level, then child menu items. I need to add a ‘top-level’ class to all menu item anchor elements who have a sub-menu. I need all sub-menu lists to have the class ‘sub-nav’. And I need to have all of the last sub-menu list items (li) to have a class ‘last’.

Here’s the code I have right now that generates my menu the exact way I need it to be generated using the get_pages function:

<?php
$pages = get_pages(array(
    'parent' => 0,
    'sort_order' => 'ASC',
    'sort_column' => 'menu_order'
));

$num_pages = count($pages);
$p = 0;

$exclude = '"pastor.php","service.php","gallery.php","audio.php","video.php"';
$exclude_list = $wpdb->get_results("SELECT GROUP_CONCAT(t1.ID) AS IDS FROM " . $wpdb->posts . " AS t1 INNER JOIN " . $wpdb->postmeta . " AS t2 ON (t1.ID = t2.post_id) WHERE t1.post_type = 'page' AND (t1.post_status = 'publish' OR t1.post_status = 'private') AND t2.meta_key = '_wp_page_template' AND t2.meta_value IN (" . $exclude . ")  ORDER BY t1.post_date DESC");

foreach($pages as &$page) :
    $children = get_pages(array(
        'sort_order' => 'ASC',
        'sort_column' => 'menu_order',
        'hierarchical' => 0,
        'childof' => $page->ID,
        'parent' => $page->ID,
        'exclude' => $exclude_list[0]->IDS
    ));
    $num_children = count($children);
    $has_children = $num_children > 0;
    ?>
    <li class="nav-item<?php echo ($has_children ? ' hoverable' : '') . ($num_pages == ++$p ? ' last' : '') . ($page->post_name === $root_parent->post_name ? ' active' : '')?>">
        <a href="<?php echo get_page_link($page->ID)?>" class="top-level"><?php echo $page->post_title?></a>

        <?php if($has_children) : ?>
            <ul class="sub-nav">
                <?php
                $c = 0;
                foreach($children as &$child) : ?>
                    <li class="nav-item<?php echo ($num_children == ++$c ? ' last' : '')?>">
                        <a href="<?php echo get_page_link($child->ID)?>"><?php echo $child->post_title?></a>
                    </li>
                <?php endforeach;?>
            </ul>
        <?php endif;?>
    </li>
    <?php
endforeach;
?>

Is there a way to pull menu items in an order multi-dimensional array so that way I can just iterate through them and generate the above template manually, instead of all this wp_nav_menu and walker none-sense?