how to customize widget list items

Hello,

I see that there are arguments for before_widget, after_widget, before_title, after_title. Is there an argument for changing the HTML before and after each list item?

Currently my output is like so…

<ul><!-- recent posts -->
<li id="recent-posts" class="widget widget_recent_entries">		<h2 class="widgettitle">Recent Posts</h2>
<ul>
<li><a href="something">apples</a></li>
<li><a href="something">oranges</a></li>
<li><a href="something">bananas</a></li>
</ul>
</li>
</ul>

What I want is…

<ul><!-- recent posts -->
<li id="recent-posts" class="widget widget_recent_entries">		<h2 class="widgettitle">Recent Posts</h2>
<ul>
<li><span><a href="something">apples</a></span></li>
<li><span><a href="something">oranges</a></span></li>
<li><span><a href="something">bananas</a></span></li>
</ul>
</li>
</ul>

-Ryan