Scrap that above, I was talking gibberish.
Almost got it... but it's not quite there in Opera, will need to tweak the CSS on the hover slightly.
Replace this in your template: note I've added the
if gte IE 6 and removed the if statement for
if IE 7<?php show_menu2(1, SM2_ROOT, SM2_ALL,SM2_ALL,'<li>[a][menu_title]
[if(class==menu-expand){<!--[if gte IE 6]><table><tr><td><![endif]--><ul>}]
[if(class!=menu-expand){</a>}]
[if(class!=menu-last){</li>}]
[if(class==menu-last){</li></ul><!--[if gte IE 6]></td></tr></table></a><![endif]-->}]','','',''); ?>
Seems to do the job.