Generally speaking, scorps from genus Scorpaenodes tend to be smaller, and may do OK with the clowns (depending on the size of the clown), as will the waspfish family. Leaf scorps would be fine, but know that they don't keep their coloration well in captivity (esp. the red morphs) and that you will likely have to feed them live ghost shrimp for life, as they are tuff to wean. They do, however, train to taking food from a net pretty easily.
Bottom line, as everyone is saying...if the fish can fit into the scorp's mouth, it's pretty much a matter of time before it's on the menu.