You could clone product_listing.php to product_listing2.php, and call for the appropriate one based on a category id or cPath test in /includes/modules/pages/index/main_template_vars.php (no override available; keep a backup and edit the core file)
around line 130:
PHP Code:
} elseif ($category_depth == 'products' || zen_check_url_get_terms()) {
or around line 196:
PHP Code:
////////////////////////////////////////////////////////////////////////////////////////////////////////////
$tpl_page_body = 'tpl_index_product_list.php';
////////////////////////////////////////////////////////////////////////////////////////////////////////////
} else {
Alternatively, you could do as the Column Layout Grid mod does and have sections in product_listing.php based on current category instead of on row/column setting.