Hmmm, interesting idea. I'm assuming you are thinking it would be a good impromtu composting toilet. Knock it onto a flat side, dig out the center, put the "holy seat" in place and you are good to, er, go. I wonder how stable they are if you try to dig out some of the center hay for the deposit area? I'm guess you'd need to put some sort of mesh retaining wall around the opening. It'd really suck to have it collapse while in use! I also wonder how much waste one of these bales could hold?

Overall, I think it's an interesting idea, but there's definitely some engineering aspects that would need careful set up.

-Blast