You have the $count variable that tells you how many items you have. You can define another variable that increments after each menu item. After this variable equals $count, you can put a different class on that last item.
Or you can cheat and put a value in extra1 indicating that this is the last page, then test for this in your template.
changing menu template
Re: changing menu template
Or like this
{foreach from=$nodelist item=node name=menuitem}
url}"{if $smarty.foreach.menuitem.last} class="last-menu-item"{/if}>{$node->menutext}
{/foreach}
Re: changing menu template
Even better! I forgot about the smarty looping position indicators.