Anyway, build. Parameters:
All books allowed
Flaws allowed
Barbarian 1 / Fighter 6 / Warblade 1 / Bloodstorm Blade 4 / Exotic Weapon Master 1 / Master Thrower 1
Flaw 1 - Exotic Weapon Proficiency (Harpoon)
Flaw 2 - Weapon Focus (Harpoon)
Level 1 - Point Blank Shot
Fighter 1 - Power Attack
Level 3 - Leap Attack
Fighter 4 - Improved Bull Rush
Level 6 - Shock Trooper
Level 9 - Knockback
BSB 3 - Hurling Charge
Level 12 - Rapid Shot
Class Abilities:
Barbarian - Lion Totem (pounce), Whirling Frenzy variant
Fighter - Dungeon Crasher (levels 2 and 6)
Exotic Weapon Master - Uncanny Blow
Master Thrower - Two With One Blow
The idea is basically to run around and throw harpoons into fat people. Since it's assumed you're two-handing them, you'll be doing double your ridiculous Str mod in damage even before Power Attack kicks in. Whirling frenzy, hurling charge and rapid shot give you 3 extra attacks on a charge (total routine: X-2/X-2/X-2/X-2/X-7/X-12; better even than a TWFer's attack routine of X-2/X-2/X-7/X-7/X-12/X-12), at range, and with two-handed/Uncanny Blow Str mod, Knockback and Dungeon Crasher tacking on 8d6 x TRIPLE Str mod at the end of that if you can smack them into the scenery. Oh, and since it's a harpoon you do all that damage AGAIN when it lightning ricochets back into your hand. I don't even want to imagine the carnage you can wreak if you put the valorous (+1), explosive (+3 on ranged weapons) and exit wound (+2?) modifiers on your weapon of doom.
Assuming I rolled a Strength of 17, I can have a Strength of 30 (base 17 +3 levels + 6 enhancement +4 racial) minimum which makes my Str mod +10. So your regular harpoon damage is 1d10(2d6?)+21, you can add 56 damage with no attack penalty on a Leap Attack charge, then double it because of Valorous, and it doubles AGAIN (not the pussy D&D-style two doubles = triple, but actual QUAD DAMAGE) when your harpoon comes flying back out through the three guys you just impaled in a row. Also, they explode and fly into walls where their pulverized remains take 8d6+30 damage.
And you can do this 6 times per round, every round. On average, about 1d10+77 x4 damage (350 damage) per hit, not counting dungeon crash damage (58 damage).
I understand that this isn't a terribly huge thing for damage over here, but the beauty of this is that it can do its damage at range - 30ft. away, minimum, and Thunderous Throw counting all ranged attacks as melee allows you to defeat annoying things such as wind wall and the like, while allowing you to combine the strengths of ranged combat (big hit volume) with the strengths of melee combat (titanic single hit damage). This is also an immensely versatile method of combat and it pleases me to use it.
For people who know of Fate/Staynight, I'm imagining this guy as Lancer summoned as a Berserker instead. Think of his harpoon as the Belly Spear and his whirling frenzy as the warp-spasm.
Changes I'd make if LA buyoff were permitted (I'm assuming it isn't) are to get rid of Goliath's LA and complete Bloodstorm Blade; the capstone is absolutely brutal and, with the Distant Throw/Shot epic feat, allows you to slay entire nations in one go, although good fucking luck getting Dex 25 with a racial penalty to it.