The most natural word order for regular sentences, and main clause of those, is OVS, and the subject is often left out. So ["Egy gyereket" (O) / "keresel" (V) / ("Te") (S)] for the main clause.

Changing the word order affects the focus of the sentence. Your sentence would put the emphasis on "Keresel", meaning you'd be asking something like "Are you looking for one child or many?" (instead of "seeing", for example).