6. Barrell Shower 

Now here is an original idea! Use the bottom of a watertight container, such as a barrel, as your shower pan. Add a cool vintage-looking circular shower curtain ring and a fixed showerhead directly above, and you've got a cool tiny shower. 

Can't find a suitable curtain ring? Take a closer look at the picture. I'm thinking that's a custom on-site creation made from some standard copper pipe.