I've been making hypothetical mono-god lists in my head for a while now, and the only way I could see myself swinging Khorne is with some "Handmaidens of Khorne" (read: Daemonettes) thrown in there...I've said this in other threads but you can take mono-god lists that aren't really mono-god lists. You just get similar looking models to take their place. For example you could take some space wolf Thunderwolves and with a bit of conversion work you can make them into what would be essentially chunky Flesh hounds. Now you could run these as Seekers of Slaanesh or perhaps Beasts of Nurgle.
I've seen kit-bashed Bloodletters with some Tyranid Gargoyle wings run as counts-as Screamers. There's plenty of opportunity here; daemons are a bit like orks in that you can make anything look daemony with enough patience and green-stuff. Tzeentch is especially good for this, being the god of change and mutant-ness... I also see Nurgle doing good with making other armies' stuff look like Nurgle stuff. Heck, add a few boils, some pus and paint it like a vegan's bowel movements and you're good to go. Tzeentch? Throw in a relevant colour scheme and just add an extra limb here, a few eyes there and obligatory tentacles and you'll be laughing.