How to make a locomotion in Mecanim with smooth crouching that can be interrupted?

How to make a locomotion in Mecanim with smooth crouching that can be interrupted?

Suppose, the crouching key pressed input triggers some smooth crouching animation which is a muscle animation clip and not just a transition. While the crouching animation is being played the crouching key might become released and so that straightening animation should be played, but from the point that has the character as low as it has reached down while crouching. I assume that can be achieved with animation blending trees, probably.

But then I am asking for an advice. How to make it a complete animation setup with Mecanim for a character that must be able to stand still in idle and walk and run and perform this slow smooth crouching that can be interrupted and played reverse from the point at which it was interrupted?