Joe,
I once built a stacked sod bunker with bermuda in AZ. The largest part of the stacked sod faced south and even though I added small irrigation heads to give the stacked sod extra water, it still toasted and just crumbled after a while. Now, I suppose a feature like that would be maintainable with enough money to have a guy hand water it three times a day all summer long, but that's crazy. Honestly, with enough money I doubt there is anything we can't maintain. We can control the temps of a rootzone, pump cooled or heated air into a green, make salty water pure, hand mow or hand water any area. So, with enough cash I don't think there is such a thing as an unmaintainable feature.