I have run my XP2100 B TBred at 200MHz (400DDR) FSB without any issues at all, using a 11x multiplier. I also have Corsair PC3200 memory...I haven't heard of too many folks hitting 200MHz with PC2700.
I don't run at 200MHz though. My videocard (GF4 4200) is not able to take advantage of the extra bandwith. I run at 12x180 (2160MHz) instead. I'd rather have the raw CPU power. Besides, 360MHz DDR FSB is no slouch. 😉