I know that feeling to well myself, I went for blue and corroded bronze on mine, I love the effect of the paint and it makes every bit of blood splatter even more visible. I think that they still look enough like some blood crazed dudes out to collect some skulls for the skull throne.
I think if you have a contrasting colour and then just some red spots (like blood) on the miniatures then they'll still stand out as Khorne models.