Not a bad idea, even Tzeentch couldn't get a hold of them because of the brighness of their commanders' head top.
You have to be careful here... because all current Chaos Space Marine (CSM) Legions are affilated with Chaos Undivided. If you add anyone else other than Alpha Legion (also Chaos Undivided...supposedly), you will tilt the balance to one of the Gods... and any good servant knows that's no bueno. I think you could add a Sorcerer class, so you don't need 1000 Sons, you could add noise weapons, so that covers the Fulgrim's Beauty Queens. World Eaters, maybe... but I've always thought there was a lil Berserker in every CSM. I think the Plague Father could have a sound argument for his beloved children to earn a 5th spot... but let's be honest, they are not as popular.
Oh man, just dawned on me (pun intended)... Red Corsairs baby! Evil pirate space marines. Duh. Easy choice.
The Thousand sons are more than just sorcerers. Sure the majority of their players (Including myself) will probably play sorcerer, but in the coming months they plan on introducing the other God-driven legions.
My vote goes out to the Thousand Sons. Sword-brother Gerhart stopped the Thousand Sons from recovering 3 Titans which was his final act before becoming Tankred
