Normally, I am the guy that only hires rarely, but when I do I also seek out Oral tops for my sessions. And you are right, most guys
"expect" to fuck, BUT I always make it clear what MY scene is, and usually the guy I choose agrees to be an Oral top even if its NOT what he was expecting.... I try to find the "biggest guys", and if they are professionals, money talks, But I agree its difficult hunt.
Good Luck.