Trying to figure out how to do this on 4.6.5 but QT decided to move shipping.php from /shipping... trying to find where they've moved it to.
Found it - include/func/func.shipping.php
Interesting, QT have already included this bit for us:
Code:
$smarty->assign("total_weight_shipping_valid", $total_weight_shipping_valid);
So I added this to /skin/common_files/modules/One_Page_Checkout/Summary/cart_totals.tpl
Code:
<tr>
<td class="total-name">Total Weight:</td>
<td class="total-value">{$total_weight_shipping_valid}g</td>
</tr>
after
Code:
{if $cart.display_discounted_subtotal ne $cart.display_subtotal}
<tr>
<td class="total-name">{$lng.lbl_discounted_subtotal}:</td>
<td class="total-value">{currency value=$cart.display_discounted_subtotal}</td>
</tr>
{/if}