there's a prestige class specifically for spiked chain users in Path of the Sword, but i haven't looked closely at it and i don't have the book handy. i don't know how useful it actually is, but it's probably worth a look. it's called master of chains and if im mistaken and it's not in PotS it's in Sword and Fist. i promise it's in one of those two and im quite sure it's in PotS. good luck.