Heavy shaking while braking

2003 Stratus 2.7 V6 ES just changed pads and rotors in 11/2008. Drove the wifes car last weekend and noticed a real bad shaking in steering wheel like it needed new pads. Pulled wheels and calipers off and pads barely had any wear and rotors were barely scratched. Replaced pads and rotors again (warranty) and still have same problem. Slower braking (0-35/40 ok) anything higher than that is nerve racking. Any thoughts?