I have a 150 gallon African tank with labs, venustus, jalo reef, elongatus, and albino compressiceps. I had 7 clown loaches. I never ever had a problem with the cichlids messing with the loaches, but I found that the amount of medication needed to cure the loaches of ich would stress out my cichlids so bad that it nearly killed them.
I had better luck keeping clown loaches in a smaller tank honestly. I kept 3 in a 75 gallon with African's for about 4 years and never had a problem.
Additionally, you might want to check into Synodontis Eupterus (sp?). I have 4 of those in my 150, and they are amazing bottom feeders. They have the appetite of a cichlid, and surely do clean up everything left over by those messy eaters.
I hope this helps, and good luck with your tank!
Clay
I am leaning towards synos, but CLs are a pretty good option too, do most ick cases outbreak when you first add the fish? If so I can just set up a QT for them. Or does it happen randomly?