The dialog from Casino Royale movie looks a bit strange for me:
Now, I'd have normally gone with only child but, you see, by the way you ignored the quip about your parents I'm gonna have to go with orphan.
Dictionary says that "to be" can be used:
To select or choose: decided to go with the pink wallpaper.
But, in the movie, James Bond doesn't choose or decide, he suggest if I understand context correctly. He could have spoken "I'd have normally suggested you are the only child", with same meaning, isn't it?