I just bought one off ebay for $65 and waiting for it to arrive. I'll let you know how it is when I get it (white w/ blue led). Ive seen them as high as $130. Ive made a rapid fire controller without the chip and it works great for COD 4 but slow for World at War.
*UPDATE*
Ive recieved my controller in the mail and I just got done playing with it and my only thought is...Holy$hit! It is one hell of a controller. Four diffrent settings on rate of fire. Works like a champ in Nazi Zombies. If this controller was ever used while in last stand theres NO escape, (I dont use last stand though).