How green are we talking? Down at the corner there's a house with green-tinted shingles, but no pistachio tin roofs within a close radius (maybe out in the rural areas...)
Green as in there is stuff growing on it, maybe different grasses and low lying plants. More popular in Europe than here, I get the impression. I saw a picture of one that was pretty steep and it had a goat grazing on it. I thought it was neat.
Oh, sounds cool. I do know some people who live in a house built in the side of a hill. The roof is flat grass (and has a sign forbidding 18-wheeler parking). Europe is great for that kind of stuff.
Does anybody have a green roof?