I saw this feat in Dragon magazine, and immediately thought of Six.
Spiked Chain Training [Multiclass]
Prerequisites: Dex 13, any martial class
Benefit: You gain proficiency with the spiked chain. You can treat the spiked chain as a double weapon and a light blade. As a double weapon, the spiked chain deals 2d4/2d4 damage, and it gains the off-hand property. For more on double weapons, see Adventurer’s Vault, page 10.
This basically makes it possible to make a good Ranger or Rogue wielding a spiked chain. A rogue could use it to sneak attack at reach, while a melee ranger could use two-weapon fighting with it, also at reach.