Bigger is better

[emoplato]

Okay, you want to be as big as possible Dragonborn(optional) Azurin Wu Jen 3/ Incarnate 3/ Mage of the Arcane Order 4/Soulcaster 10.
Feats: L1 Snowcasting, Incarnum Spell-shaping Wu Jen: metamagic x(extend spell)
L3 Cooperative Spell
L6 Practiced Spellcaster
L8 Mage of the Arcane Order: metamagic x(persist spell)
L9 Expanded Soulmeld Capacity
L12 Shape Soulmeld(Kraken mantle or Girallon Arms)
L15 Midnight Metamagic
L18 Bonus Essentia or free
What this build allows you to do be able to get full benefit of giant size the level you are able to get it. Arcane Investment feature allows you to increase the caster level of a spell invested up to 2 and Snowcasting increases it by 1, so you can be colossal by L16. Thanks to the Incarnate levels you can get access to psion eyes(psionics of incarnum) allowing you to use an augmented expansion dorje 7. This makes you Colossal++ as expansion doesn't have a maximum size and thanks to Mage of the Arcane Order you can leave a slot open for up to 6th level sorcerer and wizard spells(polymorph, greater mighty wallop,..etc). I suggest the kraken mantle as it gives damage in grapple that is bludgeoning which means you can increase its damage up ten sizes. I don't need to emphasize the importance of Polymorph especially with the right choice your reach will equal the field.

 

[Wyvernhand]

No point in both Dragonborn and Azurin together. Dragonborn loses the bonus essentia that Azurin grants. I'd either go Dragonborn Water Orc or just Azurin.

 

[emoplato]

No point in both Dragonborn and Azurin together. Dragonborn loses the bonus essentia that Azurin grants. I'd either go Dragonborn Water Orc or just Azurin.

It is why I put optional behind it, because mainly it is just to help a key stat out and a draconic aspect is nice. I also didn't know whether it would kick out the bonus feat or not. Water Orcs have a penalty to a casting stat.

 

[Wyvernhand]

So? Penalties to a casting stat aren't crippling if your primary goal is gishing.

Also, I found it.

Half-Ogre2/Monk2/PsyWar4/Totemist2/SoulManifester10

Feats
1st Aberrant Blood (Flexible Limbs)
Monk1 Improved Unarmed Strike
Monk1 Improved Grapple
Monk2 Monastic Training (Soul Manifester)
3rd Tashalatora
PsyWar1 Practiced Manifester (PsyWar)
PsyWar2 Azure Talent
6th Overchannel
9th Expanded Soulmeld Capacity (Kraken Mantle)
12th Expanded Soulmeld Capacity (Girallon Arms)
15th Inhuman Reach
18th Deepspawn

Strength = 46 (+18) (18 base + 6 racial + 4 levels + 4 Tome + 6 Belt +4 size +4 Tentacle)
Size = +12 Gargantuan
BAB = +11 with fractional BAB
Soulmelds = +20 (14 from Girallon Arms and 6 from Kraken Mantle)
6 essentia in Totem due to 4 + 1 class + 1 feat
6 essentia in Shoulders due to 4 + 1 feat + 1 item
Powers: +14 (21 point Grip of Iron)
Feats: +8 (+2 Aberrant Limbs, +2 Deepspawn, +4 Imp Grapple)
Items: +6 (+2 Armbands of Might, +4 Grappling Tentacle)
Total: +89 compared the the Tarrasque’s grapple mod of +81

Since I have monk levels, I guess I could put crossclass ranks in UMD get a partially charged Wand of Divine Power. That would give you +7 more. That feels so cheap though...

Not quite +100, eh, not bad.