Kleider machen LeuteThe key here is that it is a reversal of Leute machen Kleider [people make clothes]. Hence, it is best to start off with translating that.
Subject: ngā tāngata
Object: ngā kākahu
Ka auaha ngā tāngata i ngā kākahuI used Ka as the verbal particle because there is no real tense or aspect implied by the German. Now if we reverse it we get:
Ka auaha ngā kākahu i ngā tāngataAny thoughts?
Addendum 15 Aug 2012: What I should have commented more fully on was my choice of verb. The German word machen, like the English verb 'to make', is quite versatile and the Te Reo Māori/English dictionaries I checked don't give much guidance. So I tried to select a verb that gives the idea of creation/construction. I may have picked the wrong verb entirely, of course. Another option for the title would be to use a proverb with the same meaning as the English "the clothes make the man" or "you are what you wear". There may be such a proverb — I don't know.