Goto overclockers.com and then click on the CPU database. You can choose the CPU you want and how you want it ordered..eg: PIII450 by overclock speed or by batch number, etc... it's easier to go here and see what success people get with what chips. Let me know if this help.
I dont know any stats. I got one about 2 months ago, and a Abit BX6-2. Ran it at 450 for about a week. Then bumped it up to 558. Same heatsink and fan that came with it, and same core voltage. It runs very steady at 558, 2.0 volts. I play ALOT of games, usually for more than a hour at a time. I have alost looped the 3DMARK demo about 7 times before. No problems at all.