Well even with a basic build of Human Rogue 3/ Swashbuckler 3/ Fighter 4/ Invisible Blade 5/ Master Thrower 5 you'll end with the ability to throw 16 (BAB of 19, TWF, ITWF, GTWF, Rapid Shot, and Palm Throw) daggers a round all as ranged touch attacks and 8 of which will have 5d6 (+20 with Craven) sneak attack damage. Each dagger alone would deal 1d4+2+Int+Str. But that's just throwing the daggers, in melee that still leaves you with 7 attacks per round. There are builds out there that are better than this one in terms of damage output but this one is easier to build.
Human
1. Rogue - Point Blank Shot, Precise Shot
2. Rogue
3. Rogue - Craven, Penetrating Strike substitution from Dungeonscape
4. Swashbuckler - B: Weapon Finesse
5. Swashbuckler
6. Swashbuckler - Two Weapon Fighting
7. Fighter - B: Weapon Focus Dagger
8. Fighter - B: Improved Two Weapon Fighting
9. Fighter - Far Shot
10 Fighter - B: Weapon Specialization Dagger
11. Master Thrower - B: Quick Draw
12. Master Thrower - Great Two Weapon Fighting
13. Invisible Blade
14. Invisible Blade
15. Invisible Blade - Rapid Shot
16. Invisible Blade
17. Invisible Blade
18. Master Thrower - Combat Reflexes, Darkstalker, or Improved Precise Shot
19. Master Thrower
20. Master Thrower
Gear of Note: Gauntlet of Infinite Blades or a modified Quiver Anariel of set to Bandoleer of Infinite Daggers, Collar of Umbral Metamorphosis
Taken from Lone Drow: Companions of the Hall http://ww2.wizards.com/Books/Wizards/?doc=fr_lonedrowstats
Quiver of Anariel:Quivers of Anariel appear to be typical arrow containers capable of holding a score of arrows. However, the quivers automatically replenish themselves with standard or magical arrows, such that they are always full. Some quivers also create arrows made of special materials, such as adamantine, cold iron, or alchemical silver.
Once an arrow it taken from the quiver, it must be used within 1 round or it vanishes.
Moderate conjuration; CL 7th; Craft Wondrous Item, magic weapon, minor creation; Price 28,000 gp (standard arrows), 29,000 gp (masterwork arrows), 32,000 gp (+1 arrows), 44,000 gp (+2 arrows), 64,000 gp (+3 arrows), 92,000 gp (+4 arrows), 128,000 gp (+5 arrows); Add an additional +6,000 gp for adamantine arrows, +4,005 gp for cold iron arrows, or +200 gp for alchemical silver arrows; Weight 1 lb.