Well, I am running my tbird 700 at 933 rigft now and it seems pretty damn stable. Running RC5 in the backround and I am at 45C.
I have my multiplier at 8.5, fsb at 107/35, voltage at 1.825, and some other setting in my KT7raid at 2 (I will look it up when I reboot). Cooled with a Taisol CGK742092 with a delta 30 CFM fan.
I'm trying for 1ghz, but I think that may be stretching it.