Other Info
Here is some other info wich is nice to know about Kuja. Some of them are my own theory, others not!
Familiar?

Remember the Amano designs? Every design has a little creature next to it, wich kind of looks like the character itself! Let's call them familiars! Here's Kuja's! It kinda looks like a silver dragon! ^_^
Kingdom Hearts?
Kuja won't ever be in Kingdom Hearts! Why not? He is copyright to Amano, who designed the characters from FF1 untill FF6, and FF9. He seems not to like Kingdom Hearts, and the makers of that game won't have to rights about the characters. They do have them from FF7,FF8 and FF10 though! That's the reason Kuja will never come in one of the KH games! It could be a good thing, they might screw him up with a wrong voice-over!
Torture Room
Did you notice when you was in the Desert Palace? Close to the prisons there's a torture room located! (it's the room where the Moogle is in) You can see some handcufs, a whip and a rack. Let's just say it's a torture room and won't use them for 'other' stuff! He doesn't have a partner stupid! Kind of weird if he does it himself! So...torture room since it's close to the prisons!
Silver Dragon
My theory is that Kuja (for a part) is made out of a Silver Dragon. He has three silver feathers, and the dragons have them as well! If you watch the game closely you can see that he can control them. And remember when you want to enter Memomoria? You were ambushed by a lot of dragons! My point! ^_^ That's why I think so...but it could also be that he got the feathers from his dragon and put the feathers in himself! But that doesn't explain his hair color...while the others genomes are blond....or maybe something Garland wanted...