Most King of the Cage fighters move to UFC.
King of the cage also has a dvd out called The Fighters of Las Vegas.
Back cover:
This no-holds-barred DVD compilation features 24 fighters whose strength and skill has enabled them to compete in other fighting organizations including the Ultimate Fighting Championships of Las Vegas, either prior or following their KOTC career.
Fighters:Ricco Rodriguez, Dan Severn, Sean Sherk, Vernon White, Pete Williams, Jeremy Horn, Jeremy Jackson, Ronald Jhun, Duane Ludwig, Guy Mezger, Paul Buentello, Yves Edwards, Plus many more
http://www.kingofthecage.com/store_dvd_007.html
I could list about a dozen more that have fought in King of the Cage and moved to UFC and Pride FC