I'd still do it with the extra get parameter.
Let's say the url for the first landing page is
http: //www.domain.com/index.php?main_page=product_info&products_id=9
and the url for the second landing page is
http: //www.domain.com/index.php?main_page=product_info&products_id=9&lp=b
Duplicate includes/templates/your_template/template/tpl_product_info_display.php
save it as includes/templates/your_template/templates/tpl_product_info_display_b.php
modify it to display your product differently from the standard.
Now, edit includes/modules/pages/product_info/main_template_vars.php
Find this line of code:
PHP Code:
$tpl_page_body = '/tpl_product_info_display.php';
modify it to be
PHP Code:
$tpl_page_body = (isset($_GET['lp']) && ($_GET['lp'] == 'b') ? '/tpl_product_info_display_b.php' : '/tpl_product_info_display.php');
that way the new template file will be used if and only if the
&lp=b parameter is in the url. Same product from the database, just displayed differently.