Alternate Cleave, Great Cleave

I was thinking of modeling Cleave and Great Cleave off of the Blowthrough weapon enchancement from Complete Warrior.

The enhancement is meant for ranged weapons and does the following: If you hit your target, you can hit the target behind him. You make another attack, taking into account a +4 AC modifier.

For Cleave I was thinking something like this:

Cleave
Pre: Str 13, Power Attack
Benefit: Once a round, as a standard action, you can make a single attack against a creature. If you hit your opponent, you can follow your attack through to an adjacent creature. The target of your cleave attempt gains a +4 to AC.

Great Cleave
Pre: Str 15, Power Attack, Cleave, (Fighter Level prereq?)
Benefit: As a full-round action, you can make a single attack against a creature. If you hit your opponent you can follow your attack through to any number of adjacent creatures. Each creature after the first gains +4 to AC. You can continue these cleave attempts until you miss or run out of opponents. You can attempt a number of cleave attempts equal to your normal number of attack per round.

Confusing enough?
Here's one more.

Charging Cleave
Pre: Str 15, Power Attack, Cleave, Great Cleave, BAB +12
Benefit: You can combine a cleave attempt with a charge.

This makes Great Cleave not that different to Whirlwind Attack. Granted, WWA is rather superfluous anyway.