Actually, Feline sets up a fan club of you
Once you kill the Novice in the Abbey and put Feline there, she will create a fan club of you and start feeding you girls and boys for cash which you can turn into dark troops. Some time later in the game, after the dragon riders quest activates, so will the fake princesses idea activate, as it is clear you can't supply the dragons with so many real princesses. I think Marie Curie was the one to talk to about it.
I had a weird occurrence during the quest, though. She took 1 princess from me and nothing happened, but when she took a second, I could have the fake princesses. Dunno why that happened.
In any case, I doubt the game has been planned for a full stack of dragon riders, as that would be extremely overpowered. It is overpowered enough that you can split your dragon rider stack in 2-5 and have 2-5 separate dragon summons, which gives you a great control over the battle.