I've never met many strength coaches (football) who encouraged going below parallel when squatting....high school, college or pro. Some suggest even stopping before that break (stopping before parallel). Yes, 400+ for some high school kids.
This can included front squatting, which really comes to mean quarter, or a bit below, reps to be honest, in a sports training program (unless your a Olympic lifter, the true athlete in the lifting world) .. It's the idea of getting adjusted to handling heavier weights targeting the shoulder girdle, where you need it in football. Front squats are a exercise that must be learned. Yes, 400+ has been done.
The Zercher squat(BB resting between the bent bicep and forearm in a cradle position) can also be injected into an athletes training. It is an exceptional exercise for power performance. Used in football style workouts and with very heavy weight. Not sure of any record poundage, but have personally seen 400+lbs used for reps (ah yes, that magical 400 again).
Good Luck
(Right back at ya Wes)