Update #1:
I've made the changes as discussed below so that the entire row is now a clickable link. I have it running on both navigation blocks on my site
here. I've also attached my entire template, in case anyone would rather simply replace my URL links and colors with their own. Keep in mind that if you use my included template, you will still need to add the CSS definitions as above.
Update #2:
I've cleaned the code up a bit more to make it Valid XHTML 1.0 Transitional, as well as to get the cursor to change in Firefox. Use the following for each option link inside your template, changing the colored bits to match your own settings:
Code:
<tr><td bgcolor="#444444" width="100%" onclick="window.location='http://www.yourdomain.tld/forum/option.php'" style="cursor:pointer; background-color:#444444" onmouseover="this.style.backgroundColor='#555555';" onmouseout="this.style.backgroundColor='#444444';"><span class="portalnav">Link Title</span></td></tr>