That wouldn't quite work, actually... since it takes prolonged use to break it even at 166MHz (i.e. a month or so) - so prolly, say, 30 hours of gaming time?
The max voltage for quick killing would be easy to find, the max it'll go to without dying in the short (but still longer than instant) term would be harder. Far beter just to find the voltage at 133MHz and stick something in to keep it at that... or at least, not allow it above that, since we might end up with problems (maybe) if it was too low at, say, 25MHz (for Wolfenstein). I'm not into LCDs much (or CRTs, for that matter), but I'd be concerned that different volatges ---> different colours produced. Not that that *would* happen (someone tell me please if it does), but it *might*.
If it doesn't, though, might it not make sense to find its minimum operating voltage and lock it there to save batteries?