Lyric discussion by Angry Nihilist 

Cover art for Private Lawns lyrics by Angus and Julia Stone

It's "big shot beau's" - 'beau' defined by Google = dandy: a man who is much concerned with his dress and appearance.

The song places a bad light on city life. The people are concerned only with vanity - "pretty ladies and big shot beau's." The city may be "pretty", but it doesn't have heart ("..But they aint got what we got"); the city is shallow and aesthetically pleasing and nothing more.

I'm probably totally off, but I always thought it was "Big Châteaux" (pronounced "sha-toes"), as in a french manor.

Kudos with the interpretation :D WONDERFUL duo.