There are changes in U45 that favor TWF style:
1) The new Divine Might adds flat damage rather than ability modifier
2) KotC tree has a new to-hit/to-damage line, with up to +9/+9 bonus.
The idea of the build is to use dual longswords while centered, thanks to Whirling Steel Strike feat.
Level Split:
18 pally give us Holy Sword, Zeal, and 5th core in Sacred Defender, as it looks completely insane in U45 previews (+3 Lay on Hands, +25 HAmp, +10% hp).
2 monks give us 2 feats, Sun Stance for strength and crit, and some Shintao enhancements (+10% offhand chance and +20 prr).
Race: any with bonus STR/DEX/CHA (Drow, Dragonborn, etc).
Stats: we need 4 (Str and Cha for damage, 17 Dex to qualify for TWF, and Con for HP).
So, this might be hard for new players. Lots of Ability Tomes recommended.
Feats:
(assuming Knight's Training is available in U45 KotC tree)
(Cleaves are available in KotC tree)
1 · · Paladin(1)· · · ·Stunning Blow, Follower of the Sovereign Host (Longswords)
3 · · Paladin(3)· · · ·Completionist / Child of the Sovereign Host
6 · · Paladin(6)· · · ·Precision
9 · · Paladin(9)· · · ·Improved Critical: Slashing Weapons
12· · Paladin(12) · · ·Weapon Focus: Slashing Weapons (required for Whirling Steel Strike)
15· · Monk(1) · · · · ·Adept of Forms, Monk Bonus: Two Weapon Fighting (requires 15 DEX, assuming starting 9 dexterity, and +6 tome)
16· · Monk(2) · · · · ·Monk Bonus: Whirling Steel Strike
18· · Paladin(16) · · ·Master of Forms
21· · Epic(1) · · · · ·Overwhelming Critical
24· · Epic(4) · · · · ·Improved Two Weapon Fighting (requires 17 DEX, assuming starting 9 dexterity, and +8 tome)
26· · Epic(6) · · · · ·Perfect Two Weapon Fighting
27· · Epic(7) · · · · ·Greater Two Weapon Fighting
28· · Epic(8) · · · · ·Elusive Target / Tactician / DR: Adamantine
29· · Epic(9) · · · · ·Dire Charge
30· · Epic(10)· · · · ·Grandmaster of Forms, Scion (Arborea / Ethereal)
AP:
31 Sacred Defender for 5th core. take anything useful there is, keep in mind you won't qualify for Greater Sacred Defense (requires armor or shield, not compatible with Monk)
8 Shintao (+10% offhand chance and +20 prr).
rest into KotC / Racial.
Destiny: Divine Crusader (Tier 6 Book of War gives us another +9/+9 to each hand, for our 18 Pally levels)