Hrm, I don't think there's a feat, but there are maneuvers, items and class features.
Reflex:
Kensei PrC, 5th level subs concentration for reflex.
Action Before Thought maneuver (Diamond Mind, 2nd) same thing
Will:
Moment of Perfect Mind maneuver (Diamond Mind, 1st) subs concentration for Will
Fort:
Headband of Conscious effort (Complete Adventurer) subs concentration for Fort 1/day
I'm pretty sure there's a few more, but these are the ones I know off hand.