Probably a better way, but I altered tpl_modules_order_totals.php like so:
Code:
<?php
/**
* Displays order-totals modules' output
*/
for ($i=0; $i<$size; $i++) { ?>
<div id="<?php echo str_replace('_', '', $GLOBALS[$class]->code); ?>">
<div class="totalBox larger forward"><?php echo $GLOBALS[$class]->output[$i]['text']; ?></div>
<?php if ( strpos( $GLOBALS[$class]->output[$i]['title'], '(' )){ ?>
<div class="lineTitle larger forward"><?php echo TEXT_SHIPPING_SUBTITLE; ?></div>
<?php } else { ?>
<div class="lineTitle larger forward"><?php echo $GLOBALS[$class]->output[$i]['title']; ?></div>
<?php } ?>
</div>
<br class="clearBoth" />
<?php } ?>
Since the shipping line always (I think) has a parenthesis in it, I just check for that and output my defined text instead. It works, but I'm concerned if there is ever a case where my parenthesis test doesn't hold. Small concern though.
Thanks for pointing me in the direction. If you have a better solution, I'm all ears.