Well, you could always try Pierrot, or its Dutch original Pjerrot - Pierrot is the "Sad Clown" of Italian Comedia Dell'arte.
Or you could go for Maximus - the original circuses (though they've changed a lot since then!) were Roman, and the most important was the Circus Maximus.
Then there is Ducrow, the name of an English man from the late 1700s whose "feats of horsemanship had much to do with establishing the traditions of the circus" - perhaps a distant relation of Jonathan's?
All of those names seem to "go" with the various names of the family - but personally, I prefer Pierrot.