[Christ]

You can stop completely with reversed polarity braking, which isn't regenerative. Many fork-style trucks already do this, but it requires a skilled hand. (Foot?)

If you can give the regen phase a field strong enough to counteract the gravity-weight of the vehicle, it would remain still, but you'd have to maintain the field, which would kill your batteries in short order. (Compared to not using it.)

Unfortunately, I'm sure federal DOT requires that all vehicles have a mechanical service brake, and I think several states require a fluid-type brake as well for passenger vehicles in excess of N lbs.