I just love this idea, having a bathroom outdoors. It means that you can be one with nature. If you have some land even if it is only an acre - then this is something to think about installing. You can even have hot water by attaching gas under it if you want.
Children will enjoy this too - like a small pool in the middle of summer.
I actually got these images from a farm in New Zealand, where they offer Romantic Getaway's for couples. Which is basically an old farm cottage without power (lots of candles). An open fire for heat and no TV what more would a couple need in a getaway! They offer a simple 3 course meal and a farm breakfast, with fresh farm eggs. Plus they charge about $275 for the night!! Which, I think this is a great way for farms to make a bit of extra cash on the side.
If you need a little more information or links to farm getaway - comment.