I have been doing lots of research regarding outdoor arena footing. As I understand it, you need:
Flat 2% graded area
6" Layer of large rocks (supposedly around 4" in size)
3" Layer of limestone gravel
3-4" of footing (sand, whatever)
Anyway, I was just wondering if you think that smashed bricks (like from a demolition site) would be a possible substitute for the large rocks? I bet you could get those for cheap.