Hey guys,

I hacked the rating a little bit to show 10 stars.

Files need to be modified:

components/com_k2/css/style.css
components/com_k2/js/k2.js
components/com_k2/models/item.php
components/com_k2/templates/default/item.php
_______________________________________________

components/com_k2/css/style.css

if not modified in line 59 
change
.itemRatingList {position:relative;float:left;width:125px;height:25px;overflow:hidden;list-style:none;margin:0;padding:0;background-position:left top;}
to
.itemRatingList {position:relative;float:left;width:250px;height:25px;overflow:hidden;list-style:none;margin:0;padding:0;background-position:left top;}
_______________________________________________

components/com_k2/js/k2.js

line 69 
change
$('itemCurrentRating' + itemID).setStyle('width', percentage + "%");
to
$('itemCurrentRating' + itemID).setStyle('width', percentage/2 + "%");
_______________________________________________

components/com_k2/models/item.php

line 435
change
if ( $rate >= 1 && $rate <= 5) {
to
if ( $rate >= 1 && $rate <= 10) {
_______________________________________________

components/com_k2/templates/default/item.php

starting from line 173 to 178 you'll find this block:
<li class="itemCurrentRating" id="itemCurrentRating<?php echo $this->item->id; ?>" style="width:<?php echo $this->item->votingPercentage; ?>%;"></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('1 star out of 10'); ?>" class="one-star">1</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('2 stars out of 10'); ?>" class="two-stars">2</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('3 stars out of 10'); ?>" class="three-stars">3</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('4 stars out of 10'); ?>" class="four-stars">4</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('5 stars out of 10'); ?>" class="five-stars">5</a></li>

replace it with this:

<li class="itemCurrentRating" id="itemCurrentRating<?php echo $this->item->id; ?>" style="width:<?php echo $this->item->votingPercentage /2; ?>%;"></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('1 star out of 10'); ?>" class="one-star">1</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('2 stars out of 10'); ?>" class="two-stars">2</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('3 stars out of 10'); ?>" class="three-stars">3</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('4 stars out of 10'); ?>" class="four-stars">4</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('5 stars out of 10'); ?>" class="five-stars">5</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('6 star out of 10'); ?>" class="six-stars">6</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('7 stars out of 10'); ?>" class="seven-stars">7</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('8 stars out of 10'); ?>" class="eight-stars">8</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('9 stars out of 10'); ?>" class="nine-stars">9</a></li>
<li><a href="#" rel="<?php echo $this->item->id; ?>" title="<?php echo JText::_('10 stars out of 10'); ?>" class="ten-stars">10</a></li>

Have fun :)