I have the same problem when breaking at high-speeds. I have great tires and I had an alignment done recently. I am almost positive that it is the rotors, just haven't been able to get to them yet. Good luck!
I've never had my car wobble due to warped rotors. Warped rotors only ever got me a really nasty sounding grinding noise. If it wobbles, from my experience it's because of bad tires such as worn out thread, maybe overinflation and/or it's possible you may have a bent rim. That happened to me once to and man, it was really bad.
It could be the tires, or rims, rotors, out of alignment, or it could be worse. Tie rods ends could need to be replaces, ball joints,....you would really to take it to a shop and let them put it up on a rack just to be sure.