"Are you looking for one child or many?"
Translation:Egy gyereket keresel vagy sokat?
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).
'Egy gyereket vagy sokat keresel?' is accepted.
Keresel egy gyereket vagy sokat? is not accepted. The reason for this: there is a one child- many children contrast, so one of the contrasted parts (egy gyereket /sokat ) should be in the focus. And the focus is placed before the verb.