seem kinda broken, bull rush was originally one of the maneuvers you had to use standard or charge action to use since it can involve movement (as opposed to say, trip or disarm, which don't and thus can be done instead of an attack.). since you can move with your target.
per raw you can move along them and keep pushing them with more attacks (hack if he provoke from you as well that aoo can also push him and provoke...). as long as you still didn't move more then your allowed movement in a round.(so monks can rock this thing)
1. Once you bull rush the opponent away, you're out of luck. You can usually follow a bull rushed foe as part of the bull rush, but only if you have the movement available to do so, and you have no available movement when full-attacking other than a five foot step. So unless you can attack the new position with nothing more than a five-foot step first, you're out of luck.
2. Once you attack, your charge is over (as your full attack occurs at the end of your charge), so you have no available movement. Same result as 1.
3. Not unless the characters have reach with their unarmed strikes or natural attacks. While the movement generated by a bull rush provokes attacks of opportunity from the rusher's allies, movement only provokes when leaving a threatened square. If the two rushers do have reach (e.g., they're large), then it works fine. Difficult to set up, but fine. Note that it would also end as soon as someone fails their CMB check.
So, just to check:
Assume all hits connect and all bull rushes succeed.
SCENARIO 1
Let's say we're a Human in Light or No Armor, and we're unencumbered. We have a 30 foot speed. We attack from melee range.
Character punches enemy. Enemy is Bull Rushed 10 feet. As the character Bull Rushes as a free action, can the character continue their full attack? (See: Punch+Bull Rush again, another 10 feet; and again, another 10 feet?)
SCENARIO 2
Same character charges from 10 feet away with Pummeling Charge. How far can this character travel with their target during the bull rushes total?
GENERAL QUESTION
Does this mean that you immediately move the enemy following each Bull Rush, and so you cannot just Punch+Bull Rush multiple times without moving with the enemy?
SCENARIO 3
Two characters with Greater Bull Rush, Combat Reflexes, and Greater Bull Rush stand 20 feet apart with an enemy in the middle. They have Reach. One of them punches the enemy, sending him in a Bull Rush that leads him to the other character. Said character gets an Attack of Opportunity and immediately punches him back into the reach of the first character. Repeat until one character runs out of AoOs.
Is this correct?
The way that you're able to move with a target while Bull Rushing with every Flurry hit from the Giant Fist Gauntlets is done via the free Overrun attempt you gain with every successful Bull Rush via the Siegebreaker2 ability.
"Breaker Momentum (Ex)
At 2nd level, when a siegebreaker successfully bull rushes a foe, he can attempt an overrun combat maneuver check against that foe as a free action.
This ability replaces the feat gained at 2nd level."
Even though you don't technically have movement speed, you still get a free Overrun attempt, and that's what keeps you in range for the remainder of the Flurry+BR hits. You can opt to automatically fail your Overrun attempt and end in the space in front of your target, or you can choose to actually Overrun him and roll for it.
If your overrun attempt fails, you stop in the space directly in front of the opponent, or the nearest open space in front of the creature if there are other creatures occupying that space.
You still cannot exceed your movement speed in a given round while Bull Rushing though.
Sorry, I missed the "reach" part of the initial scenario. -_-
There are a few ways of setting up "make ALL the attacks of opportunity!", and this is certainly one of them. : )