I really like your idea of dying it to match the surrounding country. Kind of like a house that's built with local materials to fit in the location.

Many artists have used urine throughout the centuries to get the medium they need, including Rembrandt, and leather workers. You'd be in good company if you tried it, but remember the consistancy might change depending on what you eat beforehand. Try eating "natural" for a few days before you try it!

Andrew.