And actually making him move.
Alright, all I have so far is this:
CE Halfling Barbarian 1 (Halfling Rage and Unholy Fury variants)
Unholy Fury: 1/rage smite any non-CE. Uses Str as the stat that's added to your attack roll, iirc.
Halfling Rage: Normal Rage, and size-based penalties to special combat maneuvers are removed.
PB an 18-2 Str
Feats (2 Flaws):
Power Attack
Smiting Power (Can use the bonus to attack from your Smite as a bonus to bullrush/overrun attempts.)
Reckless Rage.
At level 1, this halfling has a +13 to Bullrush attempts while raging. This can easily be boosted; I'm thinking Sapphire Smite at 3rd (mainly for the bonus it grants to hit), and Awesome Smite for my 6th (to get through Cha*2 DR)
Yes, I know this is suboptimal, but it came from a thought experiment i which I tried to make a Reaping Mauler that doesn't suck.
Maybe Were-Badger, for the Strength Boost and Rage stacking? An ECL 5 Afflicted Werebadger would have something on the order of 30 Str easily, resulting in Bullrush attempts with a bonus of at least +23.