First go to
..app\code\core\Mage\Catalog\Block\Seo\Sitemap
open Abstract.php file
In it change array(50=>50) to somewhat larger value .
public function bindPager($pagerName)
{
$pager = $this->getLayout()->getBlock($pagerName);
/* @var $pager Mage_Page_Html_Pager */
if ($pager) {
$pager->setAvailableLimit(array(50 => 00)); // Change to larger value
$pager->setCollection($this->getCollection());
$pager->setShowPerPage(false);
}
}
Rest do the css changes to align the page in columns.