I thought you guys might be interested in this survey I started over at OCUK. There are some mental overclocks here. P4 @ 5Ghz, XP-m @ 3.1ghz.
http://forums.overclockers.co.uk/showthread.php?s=&threadid=17259410
http://forums.overclockers.co.uk/showthread.php?s=&threadid=17259410