1. Move to Australia
  2. Take up one of many trades (tiling, concreting, wiring, plumbing)
  3. Answer your phone. Respond to emails quickly
  4. Show up when you say you will, quote when you say you will

From my experience dealing with trades working on my house, I am confident that any tradie who is able to do these basic things would have work on tap and expand with lackeys quickly.

That'll make you a millionare!

For 100K you can ignore steps 3 & 4, and you'll still have more work than you can deal with.

Or a chef at a mine.

Seriously.

Here's a FIFO[1] position paying 80K + 9% retirement, plus it provides accommodation while you are onsite: http://www.seek.com.au/Job/mine-chef/in/perth/19143356

[1]FIFO in this context means Fly In, Fly Out. They fly you to the site for a couple of weeks, then fly you back out for a week off.

Only while the housing bubble lasts...

It's not a bubble when Sydney rents are the second most expensive in the world because of a lack of supply.

It's not a bubble when interest rates are 8% and loan conditions are amongst the strictest in the world.

It's true that prices could stagnate or even drop somewhat if unemployment started to rise. But that's a very different situation to a true housing bubble like in the US or Ireland that was driven by cheap credit and easy loans.